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Selecting the correct marine hybrid drive configuration for our Explorer Yacht was a learning curve, the biggest hurdle for us? Presupposed knowledge; we did not know what we did not know. With that in mind, selecting a good solution was about becoming educated by the various potential suppliers as it was about the final price. As in all walks of life, the lowest-cost answer is not necessarily the best. Here is an example of why. Marine Hybrid Drive - Boundaries Firstly let us set a few boundaries. 30kW electric drive on each shaft giving 60kW in total or about 6/7 knots hull speed. 120kWh battery capacity 120kW diesel at 2300 RPM, minimum speed at idle about 500 RPM. Marine Hybrid Drive - Electric Motors The first consideration is to select an E-motor that can produce 30kW. More importantly, it must do this at the speed at which the propeller will absorb 30kW, in our case, about 1000 RPM (engine) before the main gearbox. Have a look at the enclosed graph. The correct speed is where the solid propeller curve line intersects the chain dotted 30 kW E-motor curve. Look also at the other dotted 30kW E-motor curve. The difference a result of the PHT or Parallel Hybrid Transmission. The function of this device is to step down the E-motor RPM meaning a smaller, faster running, and less costly E-motor can drive the shaft. The torque required is reduced by PHT Ratio, in our case 1.5:1. You can see also that up until 1000 RPM, the available torque from the E-motor is higher than the power absorbed by the propeller at that speed. There is sufficient reserve to accelerate the yacht up to its design speed at 1000 RPM (engine). Can you also see the two solid lines? One is the propeller power absorption curve, and the other is the available engine power for various speeds. Again it is higher than the propeller curve up until the maximum rated power (120kW at 2300 RPM (engine)). The engine curve starts at 500RPM as that is the idle speed for the engine; below this, it will stall. However, the E-motor can operate below this speed; there is no need for a trolling function on the gearbox. In Hybrid mode, we can work as slow as we wish for extended periods with the diesel engines turned off. Propeller and power curves. Advantages of a step-down PHT drive There are two other advantages of this arrangement. We can drive the E-motor as a generator. At 1000 RPM (engine,) it will produce slightly under 30kW output. However, the engine can rotate at up to 2500 RPM, resulting in over 90kW generation capacity from each E Motor. With 120Kwh of batteries, we now know we can recharge the batteries from 20% capacity to 100% in about an hour. Given we can run 4 days at anchor on these batteries without running the generator, that means 1 hour or so of engine operation every four days at anchor: near-total silence, all the time! Fitting a PHT was a cost addition we believe is well justified as the advantages in this setup are manifest. It is not the correct solution for all problems, but with our power needs, battery capacity, and operating profile, it should serve us well. As I said, the lowest cost solution is not necessarily the best one. Our Parallel Hybrid Drive solution and Twin Disc main gearboxes are supplied by Esco Power in Belgium www.escopower.be. Credit is given for the illustrations taken from their web site. Read also: Wet Exhaust System Design Read also: Hybrid Marine Propulsion - Why Bother?

Vanguard will have twin hybrid diesel-electric drive systems. New technology, is it simply fashion or do they have a practical use? Their facility on yachts is not the often quoted but incorrect assumption of operation over long distances on electric power. We are not going to save any puffins this time. For the true answer, read on. Illustration - an early engine room layout showing position of John Deere 4045, step down drive from Esco Power, drive motor/generator and Power battery from Praxis Automation. Note battery positions later moved forward of the engines to improve trim (they weigh 1300kg each!). Hybrid Marine Propulsion System Design Criteria In the case of Vanguard, XPM-078, what we needed was three fold: substantial power storage capacity to limit engine hours under light load. This also allows us to remove two dedicated diesel generators, relying instead on the hybrid motors and 6.5kW of solar panels. easy and quiet implementation of dynamic positioning with flexibility to drive two propellers from a single diesel engine or no engine at all. access to environmentally sensitive areas that intend to ban operation under diesel power (think Scandanavia). In sympathy with our readers, we will divide the design considerations over several blogs as it's quite an involved topic. For this blog, let us consider issues of redundant system design, flexible shore power capability, and system resiliance. In this discussion, we will refer to the system drawing attached, N21.4051-F01, provided by Praxis Automation, our partner in this project. Read also: Visiting Praxis Automation - Part 1 Visiting Praxis Automation - Part 2 To engineers or those who cannot sleep, the full installation file is here: Hybrid Marine System Redundancy Commercial systems lean heavily on redundant system design to improve overall system availability. This consideration goes hand in hand with an understanding of MTBF or Mean Time Between Failures. Thus, there are no point in onboarding two mutually redundant but intrinsically unreliable critical systems. Essential components in both systems need a high MTBF, typically above 25-50,000 hours for each assembly. The effects are cumulative, reducing the overall system MTBF. So, referring to the drawing, we have a system split port and starboard, wholly duplicated and able to run independently. To increase overall availability further, we can connect the power batteries or generator on either side to the motor on the opposite shaft. We can also link either power battery to the vessel's 3-phase AC Grid. Hybrid Marine System Shore Power Onboard Solar power is converted to 24VDC and fed to the house batteries. Shore power at 230V 50Hz and 120V 60 Hz single phase is converted to 24VDC and fed to the house batteries. Shore power 60 Hz 3-phase is converted to DC and charges the one 60kWh power battery. 50 Hz 3-phase is connected directly to the 3-phase AC bus bars. In case of failure, both 50 and 60Hz shore power connections use the same components; they are interchangeable, negating the need to carry critical spares. Hybrid Marine Propulsion Flexible Drive System Vanguard has 30kW Praxis DC drive motors connected in parallel with 120kW John Deere diesel engines. The motors drive at 1000RPM shaft speed through a 1:4 reduction gearbox from Esco Power. At 1000 RPM, they provide 30kW of propulsion power. But, disconnected from the propeller, at 2300 full engine speed, they will generate 90kW of power to charge the batteries. 125kW capacity inverters connect to nominally 30kW motors that provide 90kW when running as generators. This gives us a degree of future-proofing and a short charge time should battery capacity improve over time. Hybrid Marine Propulsion Battery Storage Two by 60kWh power battery banks can charge at 3C or three times its maximum discharge rate, so we can fully charge both power battery banks within 2 hours. We can also drive one shaft line, propeller, and generator from a single diesel. The other motor can use generated power to provide 30kW propulsion power to the opposite shaft at sea. So two propellers can operate from a single diesel engine though at slightly reduced capacity. 30kW is a reasonably modest power, but with a slippery hull shape, we should achieve 5 knots, ample with about 4 hours running or all day keeping station near the shore. Marine Propulsion Control A duplicated Ethernet (RS485) backbone connects the engines, inverters, and controls. Standard commercial/military practice can survive multiple fault conditions in replicated locations yet still function. Ethernet connects the helm to the engine room & forepeak bow thruster. All other system cables are run centrally to the engine room. This dramatically reduces the weight of cables needed to connect various points on the vessel and to that extent parallels the move to digital switching on systems like Maretron running on NMEA2000 protocol. Read also: A Novel Water Glycol Cooling System for our Explorer Yacht Read also: Wet Exhaust System Design - Developing Basic Design Rules So there you have it, assuming everyone is still awake. Hybrid yacht design is a "battery-centric" system and provides convenience unavailable in a traditional drive line. A robust, fully redundant, flexible hybrid drive design by Praxis Automation, powering XPM-002 Vanguard to the ends of this earth. Chris Leigh-Jones One Grandfather learned to sail on his father's topsail schooner, dependent on the wind and tide. The other learned on steam turbine driven transatlantic liners. My training was on double acting B&W or Dofxord's and Alfa Laval steam turbines. But time influences all, today we have hybrid drives and skysails, my firstborn now teaches sailing to soldiers. "Plus ça change, plus c'est la même chose", it always sounds better in French.

We have a water-glycol cooling system issue with the build of our Explorer Yacht, Vanguard. We have implemented cutting-edge hybrid diesel-electric propulsion technology to achieve a litany of advantages over what has traditionally been possible. However, there is a downside. In this instance, we need to install a Water/Glycol cooling system as described in an earlier blog. This will need both storage tanks and a method of heat dissipation. What we would like to avoid is an additional duplicated sea water calling system in the engine room with attendant leak and failure potential. A passive cooling arrangement would be much more reliable. We are fortunate that our yard, Naval Yachts, is keen to work through these issues and develop a robust solution. Water Glycol Cooling System Installation: The Problem We need to install water/glycol storage tanks low down in the hull form. Not to be confused with the water/glycol cooling system used on the diesel engines. These shall remain as stand-alone systems. The new tanks will hold the cooling needs of electric drives, batteries, gearbox and hybrid drive, gear oil coolers when they are unused. They will also hold a reserve reservoir when these systems are in use. Being in contact with the underwater hull form will facilitate the transfer of excess heat from the coolant to the seawater. They will also help us significantly reduce the use of seawater within the engine room. Our calculations revealed that we need approximately 6kW of thermal cooling capacity per tank. Under static fluid conditions (such as at anchor), we need 1 m2 of tank/seawater surface to contact the fluid. I’m guessing at the system capacity, but with small-bore pipes, the system volume is probably less than 100 litres. The Solution for the new water-glycol cooling system Final design (Port Side only) utilizing space across 3 frames to produce elongated tanks with twice the surface area exposed to seawater and about 30% additional capacity. Naval Yachts initially designed two small double-bottom tanks. These sit between the engines, protected by the skegs. Each tank capacity was 150 liters with a surface area of 0.8 m2. However, for a 6 kW cooling capacity per tank, we need a larger surface area. Extending the tanks towards the stern creates an odd shape, but it’s liquid storage, so who cares. That adds an extra 0.8 m2 of tankage surface, which, at 1.6 m2 total, is now larger than needed. Looking at the tank shape, we should place the inlet at the rear where the tanks are shallow, outlet at the forward end where it is deepest to minimize aeration. We will also install baffle plates internally to direct the flow past the hull surface and prevent bypass. With 100 liters required by pipework, the reserve in the tanks is 310 liters in the port tanks and the same is for starboard. Ample volume for a thermal buffer, so the temperature is easier to control. Water Glycol Cooling System: Our Conclusion I live a life of perpetual hope. This water-glycol cooling system should facilitate removing nearly all the saltwater piping from within the engine room. Coolers will no longer need regular cleaning being free of fouling. Our internal systems should also be free from potential ice damage. If this is not a first, then it is rare so let us see how it works! Fingers crossed! #waterglycolcoolingsystems Chris Leigh-Jones Read also: Sea Water Intake System Design Proves Problematic

Time for a quick tour of our explorer yacht Vanguard with pictures taken during our recent visit to Naval Yachts. The yacht launch date has slipped (again) and is now the end of June 2023. There is no profit in complaining at this stage, all parties have their eye on the goal of a successful build, and we look forward to starting our journey in the second half of this year. An evening's lecture from Magnus Day sampling his voyages at High Latitudes. Present also was Joe Rowles our UK MCA Surveyor who attended to complete the tonnage survey so we can Flag Vanguard.. Preparing for the yacht launch Yacht Paint We are starting from the stem and working our way aft. Paint adorns the hull with the superstructure in primer — International Marine salmon orange over a hull fully faired with around 3 tonnes of epoxy. We were inclined to follow the crowd and keep her in bare marine-grade aluminum, but Sebrina intervened with her designer's eye. Some debates are not worth having, so we painted Vanguard. The final test is a scientific measurement of reflectivity, yes, pretty and shiny, but how will she fare after a season or two voyaging through brash ice? "Orange is the new aluminum" so to speak. Good if we forget our mirror. Making our way along the hull, we see the orange stopped at the rubbing strake, (currently masked off). This will be matt black, again, international marine paint. I have a perhaps forlorn hope that a spray can repair any damage. Time will tell. Two-thirds of the way down the hull, we come to the DMS Magnus Effect stabilizers or their drives, which are now fitted and flared into the hull. The rotors (not yet fitted) are treated as sacrificial and will break off on impact. This prevents hull damage and negates the need for structural cofferdams. Stabilizers work on the Magnus principle providing righting force at speeds above 2 knots. Low power consumption, no hydraulic oil, and full stowing are advantages. They will fold parallel to the hull when not in use and do not extend below the bilge line, thus providing a margin for grounding. We fitted a small rope guard on the leading edge to protect from floating nets and sargassum. It is a simple 8mm aluminum plate, somewhat weaker than the 15mm hull plate, and easily bent without damaging the hull. The right hand illustration shows the stabilizer in folded position. It's higher on the hull side than the keg so protected from grounding. Naval Yachts have yet to complete the twin skegs and rudders. We did inspect the Bruntons shaft lines and rudder stock materials that have just arrived for machining. Rudder bearings are Jefa self-aligning units identical to those fitted on Hull No 1 - Mobius. This should limit jamming if a stock is damaged. Stocks are 100% oversized in diameter, making them considerably more substantial than is strictly necessary at first glance. Shot from aft to forward showing. half completed keg. Props are smiling set in tunnels for protection and to allow larger diameter props on a shallow draft hull. Work on the flybridge continues with the installation of the navigation console. The structure carries two 24" MFD screens from Praxis running Time Zero Professional, autopilot, engine controls, jog lever, VHF, and steering. At the insistence of Akan Dumrul, our owner's rep, a small heater is provided to limit condensation. (Akan is an absolute star, and I'd recommend him to anyone with a similar project.) A selector at the central helm station accomplishes handover between helms. We designed the console slightly taller than necessary to provide weather protection as the flybridge is open-sided. Two SHOX Helm chairs are height-adjustable, so Sebrina should still have a good view. The console is orientated towards the starboard side for docking, creating more usable space on the flybridge. We have to store toys somewhere, I guess. The flybridge ceiling stops short of the sides to create ventilation under the metal structure. This will help improve their efficiency. Solar panels are flexible and will follow the camber of the roof. They also have electrical connections on the underside for clean lines. Solar panels are grouped by size and location, feeding their output to one of 5 Victron MPPT charge controllers in the engine room. We have installed 7.5kW (peak), which should be plenty for our domestic needs, even by US standards! Preparing for the yacht launch - yacht cabins fit Cabin fit-out is also progressing, with panels returning after the final lacquer coating. The Fore and Main cabins are mostly complete, with the aft cabin being a work in progress. I find our visits are increasingly necessary at this stage. An example is the aft cabin ceiling that seemed acceptable for the yard installers (average 5'8 height) but needed further adjustment for my larger 6' frame. We found room in the deckhead, and up it will go! There were a few more examples, not evident from the drawings, but that would make the difference between functional and complete pain in practice. Headroom and handrail grips are probably the most common that we spotted, followed by access and unused storage. During our visit, I counted some 20 men working on Vanguard in a last push to get her to the launch date. Naval Yachts are trying hard. Our time is drawing near, and we have assembled a team to help start the journey and to keep it safe in the remote spots we intend to visit. We took a good proportion our UK and USA based families along or the visit. Stayed at Casa Sur, an Ottoman era hotel in the old town of Kaleici, Antalya. Knowing that two years of continuous effort is due to culminate, it's a strange feeling, and a new horizon will soon become visible. Life is like that, though, unexpected, indiscernible, and forever changing around us. Chris Leigh-Jones As a random aside, I received a picture this morning. In Greece, our son Jeff, up the mast of a 45-foot Hallsberg Rassy. Better phone reception, apparently.

Happy New Year to everyone, a year of change for us is coming! After we sketched out the basics of our navigation mast and located all the major components, the time came to assemble the Navigation Light specification and place them appropriately. We are being certified under UK Marine Coastguard Agency as Category (0), the UK interpretation of COLREGs 1972 is MSN 1781 and its amendments. Not the most scintillating read, a bit confusing at times, but also a set of rules that every navigator needs to know and understand. MSN 1781 covers rules of the road, navigation lights, horns, and an ethos that accidents will be your problem, so avoid them. A copy of MSN 1781 can be found below. Armed with this, here is how the navigation light requirements flow. Firstly, to define ourselves by what we are not. Not a fishing boat or trawler, pilot boat or skiff, pusher or a puller tug or a dredger. We are not "constrained by draft" or "sweeping mines". Vanguard is a motorboat, and the length category is 20<>50m. That makes life relatively clear. So we know this category will have 2NM or 5NM range lights, marine-approved, watertight, consistent illumination LEDs. The case for double lights in the event of failure probably passed on vessels out of Class with the introduction of LED at circa 10,000 hours between failure. Besides this, we have an alarm if it happens en passage - so single bulb units and a spare LED or two. Vanguard is fitted with a Praxis Navigation Light controller and has some preset conditions covering the lights we need. Those are: Steaming At Anchor Not Under Command (NUC) Naval Yachts suggested we also add RAM, Restricted Maneuvering; not sure why, diving maybe but I was in a good mood, so I agreed. Individual Operation Shown - example of a Navigation Light Controller fromPraxis Automation. So let's look at the requirements of each in succession: Steaming Mast Head Light, 5NM, white, 225 degrees forward Stern light, 2NM, white, 135 degrees aft Portlight, 2NM, Red, 112.5 degrees port forward Starboard light, 2NM, Green, 112.5 degrees starboard forward At Anchor Anchor Light, 2NM, white, 360 degrees NUC (Underway) 2 Mast Lights, 2NM, Red/Red, 360 degrees Stern light, 2NM, White, 135 degrees aft Port light, 2NM, Red, 112.5 degrees port forward Starboard light, 2NM, Green, 112.5 degrees starboard forward NUC (Stopped) 2 Mast Lights, 2NM, Red/Red, 360 degrees RAM (Diving) 3 Mast Lights, 2NM, Red/White/Red, 360 degrees 3 views of the near complete arrangement. It's a bit hard to see the small lights but there are fitted. The two large square units on the front of the roof are OneWeb phased array communication aerials. Our mast is perhaps becoming crowded, but luckily, we can fit these lights under the surfaces as easily as above. There remains an issue, however, of interference from the mast itself. We solved this by placing a requirement for 360-degree lights as two by 180-degree lights on either side of the mast struts—a small cost bump for a robust solution, probably an insignificant cost if we needed it. There some additional rules around alignment and spacing of lights that we need to work through but in essence we appear to be complete. Time will tell. Chris Leigh-Jones Writing these Blogs is cathartic. We may believe in an understanding but in putting pen to paper, we begin to feel the weakness that exist. Should any reader have an exception or wish to add their thoughts, "up and at em", as Nelson once declared. Happy New Year to all. Useful Links for Navigation Light suppliers: Mantague (France) Hella Marine (NZ) Peters-Bey (Germany) Weems & Plath (USA)

As the build progresses, we came to the subject of hatches. How many hatches, what type, location, and which rules apply? One of those events where our owner's rep, Akan Dumrul, started asking questions, and we needed to understand an appropriate answer. To which hatches are we referring? The rear engine room access door sits below the main deck, exposed to the sea on the swim platform. It needs to be watertight and secured from the inside. It can have a small glass panel but the size is limited under UK MCA rules. Cabin light/access hatches. These three are also at the main deck level; they are glazed but will also need aluminum storm shutters. They need to be watertight and secured from the inside. One is internal and needs to be arranged so as not to foul the saloon furniture when opening. Engine room hatch. A construction detail for engine room access. We will probably weld this closed for strength and watertight integrity. There is also a tiny escape hatch, similar in construction to the cabin escape hatches but with solid aluminium cover per MCA Regulations. . We cannot glaze it per UK MCA regulations for machinery spaces. Bulkhead hatches. These are internal to the vessel. The forward engine room door needs the be fire rated, noise blocking, and watertight. The forward cabin door needs only really be weathertight. Helm door hatches Helm door is above the main deck and need to be both weathertight and securable from the inside. This door needs to be either sliding or pantograph due to a narrow port side walkway. If hinged, it must open forward per UK MCA, sliding doors can open aft. Height is 1.5m so its a step up and out grabbing a rail on the cabin roof for support. Saloon door hatches The rear saloon door is to be secured externally also as it is the primary access to the vessel. Forepeak hatch is secured at sea and watertight. If we want to access at sea, the coaming must be 300mm higher than the main deck. Hinges must be on the forward edge so any head sea forces it shut. Swim step access platform. I'm of two minds here as its so near to the waterline it seems like a leak just waiting to happen. Naval are investigating access from within the engine room as an alternative. Hatches invariably open outward, forcing them to shut by seawater pressure. Additionally, all watertight hatches have limit switches that trigger an alarm at the helm if left open. That way, we can confirm hull integrity before venturing forth. All deck hatches are flush fit, fully welded construction to maintain hull integrity and save stubbing toes!. The pipe bottom left is a drain for the seal that leads water to a convenient overboard discharge point. All internal metalsurfaces will need EPDM insulation to limit condensation. I have called out the phrase "main deck"; it is a UK MCA stipulation in so far as : At or below the main deck level, all external hatches must be watertight and secured at sea. Above the main deck level, weathertight hatches are also acceptable. While we are on the subject of definitions: Weathertight for our purposes means able to withstand water from mainly one side when at sea. Watertight means able to withstand water from both sides to maximum head about 2.0 meters after which Vanguard's fate would be sealed as this is greater than the freeboard. We understand that there are other far more rigorous definitions, for example within SOLAS and that a marine approved wheel marked door may be more capable but these are ours for our purposes. During this process, it became rapidly evident to us that hatches are not simply doors. A good number of regulations govern their design and use, developed no doubt, from harrowing experience over time. Chris Leigh-Jones If anyone had told me about the level of detail needing consideration in building a yacht, I might not have believed them at the outset. In my last career, we built custom homes of similar cost, but shipbuilding is not like construction. The detail and scope are relentless, though, to be fair, the end is now coming into sight. XPM Hull No 4 may just be a walk in the park!

The last yacht bow thruster I used ran on 3000VDC, connected to the shaft generator on a general cargo ship running with a Controllable Pitch propeller. Sometimes experience may be exciting but offers little help for a particular situation. We needed a somewhat more miniature thruster for Vanguard, so how did this come about? Firstly we spoke with the company supplying our Dynamic Positioning system, Praxis. We have a very long and narrow hull, and consequently, slewing torque from the propellers off-center line was relatively low. Add to this the length of the hull providing windage for leverage; the request was for a unit above 12kW. We will be connecting the bow thruster with our dynamic positioning system, so we need a long-run capability and proportional speed/thrust control for additional power. So far, so good. The next thing we did was examine the hull. Especially within the forepeak, fore, and aft watertight bulkheads. This defined the physical limitations of the distance across the drive shaft and shaft diameter. Further forward provides a more effective turning force but at the expense of space. A large-diameter tunnel will run more quietly, but there is a minimum immersion depth for the top of the tunnel to limit air entrainment and the keel plate to limit flow bypass. This provides the dimensional limitations to add to the characteristics in the previous paragraph. Read also: Aluminum, Fiberglass, Steal or Wooden Hulls? Read also: XPM-78 Designing the First Hull Lastly, we looked at operating parameters: voltage, current, and control. Our preference was for a design operating on the 400VDC three-phase AC voltage. We have it available in the engine room. Three phase balances each line load, single phase would drop all 15kW on to a single phase and unbalance the whole system. It removes the necessity of additional batteries in the forepeak to counteract line voltage drops on startup when using. DC powered system. Find the best Yacht Bow Thruster Then it's off to the marketplace to see what's available, which seems to be less choice than we expected. We had fallen into the realm of units designed for commercial applications and, within that, at the lowest end of designs within that scope. Our eventual selection was a 15kW unit from Sidepower. 250mm O/D tunnel, twin, skewed counter-rotating propellers. The bronze and steel drive line gearbox comes with complete galvanic isolation. We also have a long-run proportional control system using their proprietary S-Link CAN bus. S-Link is converted to Ethernet RS485 using a signal gateway. Yacht Bow Thruster Installation The first item fitted to our hull was the cross tunnel, fully welded to the keel plate and forefoot plates. Hull plates were then streamlined aft of the tunnel by creating a scollop-shaped cutout. Sidepower installation manual states that the rear wall of the tunnel should not be visible from the bow, (see enclosed photo below). This improves flow across the tunnel face when underway or in waves. The tunnel was fully welded to the 15mm forefoot hull plating and any internal stringers or frames. A generous fillet weld allowed for the corners to gain a good radius. Three-phase 400VDC drive motor was mounted vertically in the forepeak to save space. We mounted the speed control inverter in the engine room as this minimized power line currents and made control connections much shorter. The thruster will be controlled via a fully redundant ethernet backbone as part of the Praxis DP and Steering system. It's not a critical component, Vanguard will be maneuverable without it but neither should it be designed to fail. Chris Leigh-Jones I remember reading a comment on setsail.com where Steve Dashew mentions the bow thruster on an FPB-78 is essentially redundant as the vessel was in itself very maneuverable. Our hull is slightly narrower by proportion so it will be interesting in the sea trials too see if the same hold true for Vanguard. I'll let you all know in June!

Nothing is truly new on this planet. Consequently, a little sleuthing is an excellent place to start in a new design, if only for inspiration. We faced this scenario when the time came to specify the primary and flybridge helm positions. We looked for advice and thoughts on what others had previously done. Youtube - nothing. Forum - very little, Google - even less. Like a black hole where nothing escapes to the broader universe. We were short of illustrations and associated reasoning for the first time in a long time. So be it; we have a "blank sheet of paper" project! Boat Helm Design The first step was to look around at styles that we liked. We also have a shopping list of equipment we will need, plus the equipment needed to control or monitor the various systems installed on Vanguard. A lot can be learned from photo's once you recognize the various components installed. It was a start, and that blank sheet of paper began to fill. Next, we considered how we would use each item, for example, to assist navigation when underway, report alarm functions, and monitor hotel systems or shore power when in port. Beyond that, we could split equipment by the main helm or flybridge location. There was a logical arrangement somewhere; we just needed to find order in the chaos. Helm Navigation For the sake of explanation, let's consider navigation underway. We need to see a chart of some form that will also display critical metrics, such as the Course Made Good or Speed Over Ground, easy enough to represent those on the chart display. We will need Radar and, in close quarters, perhaps also the FLIR. An additional screen for those would be helpful. We need to steer somehow that brings in either an NFU Jog Lever (None Follow Up), a Wheel, or a Tiller for FFU (Full Follow Up) control. Autopilot should be somewhere if we need any freedom at all shorthanded. You will need to access Horn, VHF, and, less urgently, Navigation light controllers. Engine controls are the obvious addition, but in our case, that also includes energy management for the hybrid drives plus emergency stops that are hopefully never used. Regarding emergencies, we need to know about alarms, but the navigator does not need to focus only on a sizeable MIMIC display, so let's keep that away for now. This set of functions defines the flybridge and what is forefront on the main helm. What is left are those panels and associated information, relegated to a supporting role. The Victron Cerbo displays how we use the power within the vessel and solar performance. Deployment of the stabilizers, setting the shore power connections, radios, MIMIC displays of Vanguard's systems and alarms, Satellite Communications, etc. Do you see a pattern emerging here? Helm Lightening & Navigation Lights No systems work in isolation, so we also thought about redundancy. One good lightning strike may take out the Praxis steering system electronics, but can we still function using the Wills Ridley electro-mechanical systems buried more profoundly in the engine room? If so, a jog lever at the helm bypassing the Praxis system would provide duplication. An electrical short in the Wills Ridley steering controls would take out Praxis and the local electrical system. Still, we can rely on mechanical and hydraulic steering as a backup. Maybe I'm approaching the edge of paranoia here, but if we can gain redundancy by nothing other than a bit of thought, it's worth it. Similarly, do we connect the main jog lever to the autopilot or the Praxis steering system? If the autopilot is not enabled, it must connect to Praxis directly. Read also: Explorer Yacht Main Helm Design So having consumed a few coffees, followed by a few beers later in the day, we came up with a list of what fitted, which function they held, and if needed for daily navigation and on which helm station they would best reside. We then researched the various installation manuals and added their footprint to our growing spreadsheet. A spreadsheet of the equipment considered is available below. Naval Yachts prototyped the physical form of the Flybridge Helm. So now it was a matter of placing the equipment in ergonomically suitable locations. Once agreed upon, we would mirror this form onto the larger main helm station so that they retained a familiarity of purpose. The main helm station also carried additional navigation-related equipment, placed conveniently. Lastly, we added the remaining equipment unrelated to navigation, placed offset from the navigation systems. This is all associated with the main Helmand and not the flybridge. Shore power control, MIMIC display, Victron Cerbo display, chart light, stabilizers actuators, watch control, fire alarm system and on and on. Chris Leigh-Jones Very few times during my 10 years in the merchant navy did I have the opportunity to actively steer a large ship. My first such as in the Persian Gulf, 50,000 T parcel tanker out from Dammam. Thirty minutes of total concentration only to be told by an amused Second Mate - its still on autopilot. Hmm.

Sometimes in life, it becomes evident that others have more nerve than me! I felt this when standing on the swim platform of Vanguard , looking wistfully at the recently turned hull of an XPM-85 under construction in the yard of Naval Yachts, Antalya. The hull is massive, extended deeper, and broader than Vangaurd. 66% bigger by block coefficient, 29% by displacement. My lovely wife, Sebrina, began asking awkward questions, starting with "W hy can't .... .". I answered, " someone will need to hire a crew ". Silence fell upon a scene of strained marital bliss. Picture shows hull of XPM-85 prior to being skinned, scantlings are well in excess of Code requirements. The figure for scale is my friend Don Gregory, Extra First Class Engineer. Hull Statistics For those who know of the FPB 78, Iron Lady, Cochise or Grey Wolf II, the XPM 85 fills a similar space with comparable hull statistics, propulsion power, and internal arrangements. Look HERE for a similar comparison of the FPB70 and XPM78. Hydrodynamics being what they are, I'd anticipate a similar in-class performance. Hull No 1 is under construction, over twelve months into her 20-month build. Hull No 2 has gone to contract, and we hope to see the signature soon. The race is on. Compare the Hulls To compare the hulls, look at the table below listing basic parameters for XPM-78, XPM-85 from Dennis Harjamaa at Artnautica, and FPB-78 from Steve & Linda Dashew. XPM- 85, hull turned. XPM - 78 in the background. ​ XPM-78 XPM-85 FPB-78 Length (M) 22.4 25.4 26.27 Beam (M) 5.13 6.2 6.1 Draft (M) 1.3 1.6 1.4 Displacement (MT) 41 52 55 Power (total kW) 270 (Hybrid) 370 (Diesel) 340 (Diesel) Solar (kW) 6.5 6.3 N/A Class MCA Cat (0) MCA Cat (0) MCA (0) & Others Notes in build in build 2 sailing I'll keep this blog short as we have prepared a detailed video describing the project. I hope you all enjoy it, feel free to add a comment or two! Read also: XPM-78 Designing the First Hull Read also: Aluminum, Fiberglass, Steal or Wooden Hulls? Acknowledgement to: John Johnson ( yachtbouy) for preparing the Youtube videography Andrew & Lili (the owners of No 1) for kindly allowing me to write about their personal project. NB : FPB-78 "Grey Wolf II" is currently for sale. Contact Sue Grant of Berthon International. Sue.Grant@Berthon.co.uk Chris Leigh-Jones The Hull of XPM-85 reminds me a little of an experience I once had at Hyundai Shipyard, Ulsan, Korea, in the 1980s. I was standing on the key looking at four gas carriers under construction in their drydock. One was minus the stern section, so I casually asked where it was. The answer: wait for it, wait - "you are standing underneath it"! Quite a surprise I had at that moment.

To be truthful, my wife and I have an arrangement, well, several, though this blog is about one in particular. My opinions generally hold sway over hull and machinery, but when it comes to aesthetics so interior spaces of our explorer yacht, then Sebrina gets to choose. I may object or attempt to steer, but the impending discussion needs balancing against the potential strife. So it was when we began the journey to design the interior of our XPM explorer yacht Vanguard and how it would function in support of that journey. There are some restrictions, and I will attempt to cover those below. Explorer Yacht Interior Design: Firstly the layout in general. XPM-78 Hull No 1, Mobius, was built to meet the requirements of her owners. One master Cabin and one Cabin/office. We wish to sail with our remaining child and with friends. That dictated three cabins, also typical of a yacht this size. "Nothing like preserving the resale value", also helps. A hull near 80 feet should be able to support four cabins, but remember that her beam is relatively narrow in support of hydrodynamics. It's slightly less than the contemporaneous FPB-70 design. Internally there is less room than a typical 80-foot "Down Easter." To reduce the visual height of the saloon, we added short bulwarks to the hull forward of midships with two large freeing ports each side. We added three feet to the saloon and moved the helm forward accordingly though its still not too far from midships. Short of creating a party boat, that was about all we could fit into her slim frame. Early General Arrangement showing changes in cabin layout as colored overlay on top of XOM-78 No 1. Vanguard Specifications, Photos & Videos We fitted double beds in two cabins and bunks into the third. I'm not a fan of double beds at sea; I always preferred narrow beds and lee cloths that keep you snugly embraced. Sabrina's answer was strident and included, "well, we have stabilizers." Sometimes you have to go with the flow. Read also: Yacht Ventilation for Worldwide Travel Read also: Designing a Boat For Our Personal Use Rules of the Explorer Yacht Design Game We also discussed a few design rules that were easy agreement. Maximizing headroom, storage wherever possible, and many hand grips designed into the topography to be less noticeable. Blinds and radiant heat films on all windows. Addressable smoke alarms in each space. Bathrooms in each cabin, I keep calling them Heads, but that's just confusing to family. Lighting to be dimmable. Limber holes for access everywhere. Explorer Yacht Interior Design: A few more details We insulated everything metal against condensation. We also considered all the inaccessible tank-to-hull crevices and had them epoxy filled rather than risk water pooling. One luxury we did agree upon was heated towel rails. We opted for electric heating as we have substantial solar panels and battery storage. Towel rails use <300 Watts each, thermostatically controlled. The alternative would be using the Webasto diesel water heater; we may still implement that option, but let's first see how the electric ones work. Anyhow, enough of my ramblings. Here are some visuals to give you an idea of where this is going. (Colors may vary, and the main helm is incomplete.) Explorer Yacht Saloon Design This blog shows 3 variations. The preliminary general arrangement - bench seat starboard faces forward. The plan rendering above, no helm door, bench seat starboard faces aft The renderings below. Helm door added, bench now a teaching station for home schooling. Explorer Yacht Master Cabin Sebrina wished we had been building the XPM-85. Small is a relative term. The beams cover frames with the deck head raised in between helping increase overall height . Explorer Yacht Second Cabin (Son's) Slightly concerned about placing the end so far forward but the fallback is to sleep on the bench seat when at sea. Explorer Yacht Third (Guest) Cabin The door is a water tight door to the engine room (Bofor Marine) allowing access at sea from other than the swim platform. Both bunks have privacy curtains. Chris Leigh-Jones I grew up in the UK in the '60s. As the youngest, I was consistently awarded the smallest room in the house as my bedroom. At sea, I got similarly used to small ships' cabins. Now I'm American with an American family. Size is a relative term and cultural expectations do not converge in crossing the Atlantic!

In earlier days, I sailed on everything from 1950's vintage General Cargo ships (see below) through to what were, at the time, modern container ships. Maintenance of all these was at one end "in our heads" and the other "a well-documented plan created by others." The former never really worked out too well. As we head toward the launch of Vanguard, the thought lodged that we will need a system to keep tags on everything lest I loose my marbles in my approaching dotage. Yacht Maintenance Management Software The world has thankfully moved along since my seagoing days. A short while on Google revealed a dozen or so potential packages that would fit the bill of providing onboard documentation and maintenance systems and a web-based link to backup copies ashore. If you go down the route of a well-equipped explorer yacht for short-handed operation, you will need some help tracking equipment and maintenance. So, just what were we looking for: A planned maintenance system for all equipment (that's the major ask) An electronic repository for all installation and maintenance documentation, saves space A list of all equipment fitted, what system, and which manufacturer? Manufacturer or agency contact details A system that could work independently of web communications but with a shore-based backup. The three screen shots here show how Vanguard's equipment can be organized by Location, System or Equipment Family. Private Yacht Maintenance Software As suggested previously, there are many commercial systems available. We are not recommending any particular system but more a retelling of experiences with a single one. The system we eventually picked is Vessel Vanguard Pro from Baxter Marine. The name was a coincidence, by the way. It seems to have morphed from a similar aviation-based product. Baxter charges a modest yearly rental for support, I've tested that support, and it was helpful, especially in the early days (see link below). They have graciously allowed us unlimited time initially to populate the system while Vanguard is under construction. The yearly fee will start on commissioning. The 6 screen shots below show how an owner can drill down from overarching vessel details and upcoming maintenance tasks through to specific equipment, equipment details, down through maintenance and operation documentation. With a little effort, we mostly get what we want, and after a few weeks of amateur fumbling, the system has provided robust and easy-to-use. The software suggests an initial system configuration, which you can modify to suit your needs. Their library of manufacturers has proven a helpful timesaver. However, with any open-access platform, it tends to get messy with multiple entries of similar names separated by typos or locations. One part of the offer I particularly liked was their initial pre-loading of equipment from our growing spreadsheet. In these modern times, almost every manual is available for download from the web. It's pretty mind-numbing work, and I was grateful to share the pain. Once up and running, there is a growing sense of ownership of the data as minor updates and amendments fill out the blanks. "Little things...little minds". We have yet to load fully and integrate warranty, maintenance, and excess inventories, but that can wait until the commissioning of our Vanguard. Maintaining the system is a lot easier than the initial set up. Kind of handy as you get out as much as you put in on an ongoing basis. So as long as run times are updated regularly you will have planned maintenance tasks scheduled ongoing. You'll also get transparency in the form of maintenance and event history going back to the launch date. You also get an audit trail of manually entered or autogenerated logs for all the system features. So at least that's one potential headache replaced with a process and a system that anyone on the crew can operate and that takes up practically zero space in its operation. Chris Leigh-Jones UsefulLinks: Deke Kennison dkennison@baxtermarinegroup.com Vessel Vanguard Pro I miss my days on that general cargo ship. MV Donga, Elder Dempster Line. Pretty old and broken; fix the Weir steam boiler pump with a crowbar, light the boiler with a flaming rag, and duck for the blowback. Open faced DC switchboards, 4-cylinder opposed piston B&W main engine. Freetown West African crew, dodgy food, Tenants canned beer, and great shipmates. Acknowledgement to Rene Beauchamp, shipspotting.com Read also: The Interior Space of Our Explorer Yacht Read also: Two Explorer Yachts, Two Design Philosophies

I had a hangover today. My brain was punishing me somewhat, so I decided on revenge and served it some likewise treatment. Today we looked at the ventilation system for Vanguard's accommodation. The process gets a bit technical, so I will try writing this blog backward. Start with the proposed outcome, then progress to a solution. Yacht ventilation systems: The requirements On a sailing yacht, ventilation is about creating a steady spray-free draft to cool interior spaces and, if lucky, some HVAC when the generator is available. Our problem is different. Conserve energy Minimise risk of down-flooding Happy wife, happy life. My ever-loving wife, Serbrina, gets hot when she sleeps and does not like it. So if I am to avoid receiving low-level grief "ad nauseam," her sleeping facilities must be cold. We have spent the last 12 years in Charleston and Savannah on the US East Coast. A semi-tropical climate with winter in the 50s (deg.F) and summer in the high 90's. Summer relative humidity is typically 85%, so it's hot and annoyingly sticky. Our livelihood was housebuilding. This necessitated a healthy appreciation of basic HVAC and hygrometry principles (Heating, Ventilation, and Air Conditioning). Before I wax lyrical and bore anyone rigid; how does that affect today's issue? The Short Story. Cool the air once, use it twice. Make-up air flows to where the crew occupies. The saloon HVAC works hard and dehumidifies the air as designed. The cabin HVAC works efficiently by cooling the saloon's already-dry air. Excuse the hand sketch! The line diagram shows how the saloon takes air from outside then hands off to the cabins as needed. Cabin fans only run when cabin is occupied. Suppose technicalities are not your sweet spot, then probably best to stop reading at this juncture. Yacht Ventilation Systems: The Engineer's Story, Three Facts I'd Like to Introduce. Latent heat of water evaporation at atmospheric pressure: 2200 kJ/kg (water). Enthalpy of dry air at atmospheric pressure: 1 kJ/kg.deg.C Enthalpy of water vapor at atmospheric pressure: 1.86 kJ/kg.deg.C Using the above numbers, it takes something like 220 times the energy to reduce the temperature of 1kg 100% humid air from 100 to 0 deg.C than it does to reduce the temperature of 1kg dry air by 100 deg.C. That is a lot of energy. Hurricanes happen because of condensation as all that 2200 kJ/kg of energy is released into the upper atmosphere. On a large yacht such as Damen or Sarp Yachts, fresh air make-up will be dehumidified before flowing to the chillers. We do not have the space to do that so the next best solution is to use the Saloon chiller units as the de facto dehumidifier. In practical terms, then: Heating dry or humid air by 1 deg.C does not need much energy. Cooling dry air or humid air that remains above its dew point (100% humidity) takes a bit more energy, but it's still not much. Cooling 100% humid air below its local dew point is energy intensive. The illustration shows how energy content of dry and saturated air change with temperature. We need to stay on the blue line as much as possible to maximize system efficiency for a given cabin temperature. So we need to heat and cool Vanguard's interior spaces. The local Webasto installer has completed those calculations, and I accept that. But we also need to provide fresh air into these spaces, and there are rules around that supply. Referring back to our homebuilding experience, we looked at the International Residential Building Code, or IBC for short. The most commonly used version is dated 2018 with new ones released every 3 years or so. Yacht Ventilation Systems: Outside Air Requirements 2018 IBC Guidelines for ventilation of residential spaces. Note: 1 Cubic Foot per Minute (cfm) = 0.03 m^3/min 0.35 air changes per hour, calculated based on the total floor area 15 cfm (cubic feet per minute) per person Kitchens: 100 cfm (intermittent) or 25 cfm (continuous) Bathrooms: 50 cfm (intermittent) or 20 cfm (continuous) We have HVAC air handlers in each conditioned space, but we still require outside makeup air similar to the above guidelines. We also need to minimize the risk of down flooding in case of a broach, be space and especially energy efficient. Yacht Ventilation - Solutions for Temperate Climates The HVAC is not required, relying instead on natural ventilation, either in-line fans at the helm station or simply leaving doors/hatches open when appropriate. Cabin vent fans will ensure local circulation when occupied. Yacht Ventilation - Solutions for Cold Climates Turn the heating on, and in all else, the above also applies. Yacht Ventilation - Solutions for Hot Humid Climates Condition the incoming air once, and use it twice; use follows how cabins are occupied. Remember 2200 kJ/kg to condition/dehumidify (water vapor) and 1-2 kJ/kg to cool (air) after that. You cannot cool air that is 100% humid without first removing the water to reach the local, lower dew point. Introduce only dehumidified air to cabin spaces to minimize mold and mildew risks. Use existing extraction fan systems to drive air through the hull. The air inlet to the saloon will be fan (twin) assisted and restricted to a single location above the main helm. Air will flow aft across the saloon and out or into the cabins. Note the galley has its own independent extractor unit to limit propagation of cooking smells. (no bacon smell when seasick!) Cabin air will draw from the saloon (not from outside). The saloon air will be free of spray and salt and already dehumidified by the saloon HVAC. It will thus also protect from any down-flooding risk. Air will be extracted from the cabins using the bathroom exhaust systems, but they operate only in an occupied cabin. Air will enter the cabins with the passive transfer ventilation relying on a slight pressure gradient induced by the bathroom extractor fans (exhausts). The exhaust ducts are backflow protected. The laundry area has its airflow system utilizing the combined washer and dryer with an external vent. Well, that's the theory; let us see if it works! Chris Leigh-Jones We sketched out our system, and eventually, the head returned to its normal fuzzy state, free of conditions otherwise chemically induced. None of us live or work in a vacuum, so I'd be interested in any feedback available for the collective mind and experiences of our readers.