Month: November 2023

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Bidirectional DC-DC Charging

When the bow thruster was installed, two 100 amp lithium batteries were located under the V-berth. These batteries were also used to power the new windlass. The batteries under the V-berth were connected to the house battery bank in the engine room via a Victron Orion DC-DC charger. This approach has the advantage of requiring smaller gauge wire (4 gauge) and the different chemistries of the V-berth (lithium) and the engine room (coiled AGM) are made compatible via the DC-DC charger. During passages (when the bow thruster and windlass are not used), it would be nice to use the batteries at the bow as a rainy day fund for the house batteries. Unfortunately, DC-DC chargers are uni-directional. To solve this problem, a second DC-DC charger was installed. However, there is a problem in that both DC-DC chargers cannot run at the same time (or they would fight with one another. To solve this problem, I used the remote on-off connection on the DC-DC-charger. While the switches on the two chargers could be linked in several ways, I chose to use a STDP (single-pole double-throw) switch connected via the “low” pins on the DC-DC chargers.

The second DC-DC charger was located under the V-berth with the other charger.

The SPDT switch was located in the engine room. Switching it to the right moves energy from the V-berth to the house batteries and switching to the left moves energy from the house bank to the V-berth.

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New Windlass Installed

The original ground tackle for Aegir-Ran comprised 200′ of 5/16″ BBB chain and a 45 lb CQR anchor. I wanted to upgrade to 3/8″ BBB and a 55 lb Mantus M2 anchor. Unfortunately, I could not get a 3/8″ BBB for the original Monica Marine 500 windlass. Futhermore, the windlass is about 50 years old, and probably due for replacement. I chose a Lofrans Tigres horizontal windlass. While the replacement windlass is similar to the old one, its footprint is somewhat different. The old windlass partially sits on bow sprit.

It overhands the bow sprit about an inch on the port side, and a block of wood was glued/screwed to the bow sprit to accommodate the overhang. The Tigres windlass overhands both the port and starboard side, but mostly the latter. Furthermore, the spurling pipe on the Tigres is integral to the windlass. This is a bit of a problem because the Tigres is designed to be mounted directly to the deck. To accommodate the Tigres, it was necessary to build a base. I began by removing the old windlass. This was challenging because the base of the windlass was glued to the bow sprit. I drove thin metal paint scrappers between the windlass and the bow sprit. Eventually it was freed, effectively breaking away some of the wood.

The wood spacer (shown on the port side of the bow sprit was also removed with a chisel. The hole in the deck for the old spurling tube was filled with a piece of recessed 3/4″ marine plywood and the wood was patched with epoxy and fairing compound (West Systems 407).

A spacer was constructed using the CAD file for the Tigres windlass. The spacer was constructed of waterproof 12 mm birch plywood using the serviced of SendCutSend.com. The plywood was epoxied together to the desired thickness, then glued to the bow sprit using West Systems 402. A small spacer was also made for the port side, the wood was fiberglassed, and fairing compound was used to smooth the surfaces.

stainless steel insert was made for the spurling tube using a piece of 2″ round tubing that was partially fattened and flared.

The tube was carbosiled into the chase.

The deck switches were installed and the bow sprit was spray painted with Awlgrip.

The new windlass had to be mounted in a way that it can be removed from studs (as the bolts are long and cannot be lifted out past the windlass). It may be necessary to remove the windlass for repair as the Sampson post prevent the back of the case to be removed.

The solenoids were located in the anchor locker and the wires were relocated away from the spurling tube.

The windlass is powered by the two 100 amp lithium batteries that were installed under the V-berth when the bow thruster was installed.

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Prop Pitch Changed and Prop Treated with Propspeed

Aegir-Ran is fitted with a Max-Prop V.P. feathering prop. It seems that the pitch was set wrong because hull speed (about 7.5 knots) could not be achieved at maximum engine speed. The prop is 16 inches in diameter and was set at an angle of 14 degrees (a pitch of 7.6). In principle, it is easy to change the pitch, even while the boat is in the water, by removing a screw, pulling back on a collar, and setting the new angle.

Unfortunately, the collar was frozen by calcification and dirty-packed grease. Also, the prop was fouled by barnacles after only being in the water a few weeks. Taking advantage of being on the hard, the prop was disassembled and cleaned with muriatic acid to remove the calcification. Even after cleaning, the collar on the hub would still not budge. After alternately soaking the hub in muriatic acid a gasoline, the collar could be forced partially back by taping with a wooden block, but it could not be completely pulled back to allow the collar to be turned. Using a gear puller, I was finally able to force the collar back only to learn the collar would only rotate a couple of degrees. By soaking the collar in gasoline and working it back and forth I was eventually (after a couple of hours) able to force out the calcified/hardened grease such that The collar could be rotated up to 20 degrees. The prop angle was set to 18 degrees ( a pitch of 9.8).

To deal with the fouling problem I decided to treat the prop with Propspeed. The product is expensive, but has a good reputation. The components of the prop was prepared according to the directions (finishing with sanding with 80 grit sandpaper to provide a surface for physical bonding).

There are four steps to treating the prop with Propspeed: 1) wipe with Propclean, 2) wipe with Propprep, 3) paint with two coats of an etching primer, and 4) apparition of a clear coat. The entire process is time sensitive, so it is important to read the instruction and have all the materials. It is also useful to watch the video.

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Installed New Solar Panels

Last year I installed two Renogy 100 watt semi-flexible solar panels on top of my bimini. I have noticed that their performance has been degrading ever since they were installed. I also noticed they were starting to become brittle. Originally, I had designed the bimini so it could be removed without too much trouble, but in the past year I never removed it. There were problems with the design of the bimini too. The edges had curled such that the bimini would collect water. I was going to reenforce the bimini by installing some fiberglass rods, but when I saw what had become of the solar panels, I decided to replace the bimini altogether. I decided to install two rigid Renogy 175 watt panels (like the three 100 watt panels on top of the hard dodger, which were chosen because the fit neatly between the hard dodger and the two backstays.

I began by installing two additional steel tubes from the frame to which the panels on the hard dodger are mounted to the steel tube hoop in the stern of the cockpit. This was easily accomplished using 90 degree tee fittings (the same way the frame for the panels on the hard dodger were mounted). 0ne and a half inch wide aluminum bars were bent slightly in the middle and the panels were mounted to them. The panels were then mounted to the tubes using stainless steel U-straps.

To conceal the wires and afford some protection for the underside of the panels (and my head), I sewed liners out of Sunbrella. The liners are held on with snaps, The bottom half of the snaps are screwed into the aluminum frames of the panels and the top halves of the snaps are installed in the fabric.

The three panels on the hard dodger are wired in parallel (because there is a risk of partial shading by the boom, which would significantly reduce performance if wired in series). However, there is less risk of partial shading of the two new panels over the cockpit, so they are wired in series, which reduces the amperage (while increasing the voltage). I have read that panels that are wired in series tend to perform better under low-light conditions (e.g., at sunrise/sunset or cloudy conditions), probably because the “band giap” is smaller for panels wired in series compared to panels that are wired in parallel.

Although the upgrade increases my solar capacity from 500 to 650 watts, initial tests suggest the two new rigid panels are twice as efficient than the old flexible panels. It seems like the capacity has almost been doubled.

I will note that the new solar panels and frame also significantly strengthens the stern pulpit. I have not been very satisfied with the strength of the outboard engine mount. I intend to redesign the mount with the now-strengthened pulpit. Also, t is my intention to sew removable side panels that will mount to the tubes under the panels and the stern pulpit to provide some additional shade and protection from wind/spray.