We reviewed how the Windlass would mount on our last visit to Naval Yachts.
The device must perform several functions, including raising/lowering the anchor, breaking and /or locking the anchor chain in a particular position, and providing motive power for warping a headline or kedging an additional anchor when necessary.
The Windlass is a large Maxwell (now Vetus) VWC4000 design with an attached vertical capstan, band break, and Maxwell chain stopper attached separately.
By "large,"; it's not that big but represents the smallest of their range of Windlass for "large yachts 80 feet and upwards".
Essentially, the system is a commercial-grade unit. The anchor chain is 330 feet of ½ inch (13mm) galvanized chain attached to a 110kg Rocna anchor. We thought about a. stainless chain but consider them inferior on both cost and corrosion performance (crevice corrosion). Sometimes bling has no place on a. yacht. I claim no actual knowledge on anchors but was accepting to follow the advice of others, in particular Wayne, owner of XPM-001 Mobius, and Dashew on the FPB70 and FPB78.
The anchor is about 50% larger than recommended for this displacement and hull length, even given the low windage. We followed the philosophy that you could never have too big an anchor, and everyone likes to sleep at night. It is stowed in a rack on the port side, preventing the need to have it protrude in front of the hull like an ancient Greek Trireme. We will probably also store an additional demountable anchor in the forepeak, just to be cautious. Mantus make this type of anchor.
The forward facing fairlead is set at deck level. It will be used for the anchor snubber as well as tow lines and sea anchors. It also acts as a drain for water that lands on the forward sloped foredeck. That stem is just sooo skinny!
Returning now to the Windlass. An essential aspect of the installation is ensuring that the anchor chain and mooring lines run free and correctly set onto the drums. In this respect, our initial intention to fit the unit onto the foredeck proved problematic. The anchor chain ran fairly into the Windlass and onto the chain locker, so that was correct. However, we noticed that any line that led through the forward fairleads and onto the capstan drum joined the drum approximately at the midpoint (see below). The user could force the rope lower but then risked it overrunning itself, resulting in a nasty and dangerous tangle. This is no good even on a nice calm, warm day; imagine if windy, wet, and freezing.
When installed on the foredeck the warp led to the capstan at a down angle from bulwark to capstan drum risking an overrun as shown in the right hand drawing.
The answer was to raise the assembly above the foredeck level. Luckily the windless drive gear is designed for a thick wooden deck installation, so the retaining bolts were some 4inches long. The new position allows for a horizontal run from the bulwark and fairlead to the base of the windlass drum. We can get at least two and probably three turns on the drum before it exits the top of the capstan drum. That should provide a firm purchase on our near 1" diameter mooring lines.
By raising the unit 100mm or 4", the warp leads horizontally to the base of the Capstan drum providing 3 turns of grip and reduced risk of overrun.
We looked at ways to power this Windlass from hydraulic to 24VDC with a local battery bank for peak load, 240VAC, and 415VAC 3-phase. The final choice was the 415VAC 3-phase. This minimized the cable weight and voltage drops between the engine room and a nearly 60-foot run to the Windlass. Luckily we have 415VAC bus bars available. Failing their existence, we would probably have opted for a 240VAC single-phase supply as it avoids the installation of a heavy battery bank at such a forward location.
Advice from Magnus Day of High Latitudes was that we would experience problems with glacial flour (goopy silt) adhering to the chain and anchor. Our solution was to provide a high-volume jet of seawater driven from the fire main. It will flush the main regularly and clean the chain as it comes back on board. The sea water flow is considerably larger than a typical wash-down provision, be careful where you stand!