Repowering Solitaire

After 35 years and about 3,000 hours of operation, it is time to give Solitaire a new propulsion system. The Volvo MD7A was beginning to smoke, and for the second time the 110S saildrive lower unit had been destroyed by electrolysis. Purchasing a new power plant, not including installation was around the value of the boat. Being a handy fellow I decided to do it myself. Today I am at $7782 after boatyard costs including a bottom job.

The first step was to remove the old diesel. The MD7A produces 13 HP and weighs a massive amount for its size. In the interests of safety I disassembled it in place and then hoisted it out and into a dock cart with the main halyard. The saildrive must remain until the boat is hauled out, and I replace it with a conventional propeller shaft. There is a lot of fear about removing a diesel engine from a saildrive with the boat in the water.  If the big diaphragm is inadvertently pulled out the boat could rapidly sink. If you take your time and don’t get rough I personally think the risk is low.

I then had to find a new diesel engine. I chose the Kubota D722 because it is in production today, it is common, it is used in many boats, and parts are cheap. It also boasts 20 HP which would benefit Solitaire when motoring into a chop. I was prepared to fully marinize the diesel myself, but I found an Onan genset for the right price if I removed it, so I did. That way I acquired the marine exhaust manifold and the heat exchanger.

In retrospect it may have been easier to have gotten a low-hours D722 out of a skid-steer or something else and then bought a Bowman manicooler. Alas we are way past that decision now. I fabricated the bell housing and damper plate out of generator pieces. I welded up the mounts and the brackets for mounting the 100A Balmar alternator I already had. I obtained a Hurth HBW-10 gearbox from Ebay that may well turn out to slip when loaded up, but again parts are cheap and the price is right. We shall see.

And here is the running diesel ready for installation (I hope)

The Volvo instrument panel had to go. I designed and built a replacement with the gauges and switches that I felt were most important based on my experience. Battery charge rate, engine temperature, and fuel level are more important to me than oil pressure and voltage for instance. The tachometer is separate, and is also being replaced with one that records engine hours. The benefit of running the engine on the stand is that I could check the function and calibration of all the gauges in advance. I replaced the key switch with a start/run/stop switch. Other switches include glow plugs, alarm on/loud/mute, and an auto shutdown switch.

The next step was to replace the 13-gallon diesel tank with a 30-gallon Moeller tank. Replacing the tank has to take place with the engine removed. I really wanted a 36-gallon tank but I would have had to custom make it in order to leave enough room to access the back of the engine. I think I found a good compromise.

5/16/2015  This week I began work to build the bed logs that the engine mounts rest on. I’ve seen them made out of wood with fiberglass on top. Lag bolts are then used to secure the engine to the boat. I’m afraid I just don’t trust wood enough however. Blame it on Conan the Barbarian and the “riddle of steel”. I am therefore waiting for my 5/16″ X 3″ X 20″ steel plates to come in. I will glass them in and then tap them for threads.

But first I had to remove sections of the old saildrive pan to make room for the new engine bed. I carefully drilled some small holes in the pan first to make sure it wasn’t somehow flooded inside. I then made short work of the pan with a sawzall, being careful not to saw a hole in the bottom of the boat. This is far as I could go with the boat in the water so it was time to head for the boatyard.

5/22/2015  The voyage across Clear Lake to the boat yard was accomplished thanks to Sharktypus and my 5Hp outboard. With the dink secured to Solitaire’s stern quarter, she made about 3kts. The water level in Clear Lake remained 2ft above MLLW due to a stout southeast wind. This resulted in 6″ of water between the keel and the mud bottom.

Removal of the saildrive drain plug was still possible. Water drained out for a while, but then turned into a stinky mix of emulsified oil and water. I captured and recycled the contents. Afterward, removal of the saildrive was straightforward. Once the six 17mm bolts were removed from below, both halves could be carried off, never to be seen again. I then set to work removing the rest of the saildrive pan. With the sawzall it was a breeze. I then ground down the fiberglass adjacent to the hole, and Abraham, the awesome fiberglass/paint guy from Morales Boat Repair, filled it in.

5/29/2015  Then it was time to install the new shaft, shaft coupler, strut, stern tube, stuffing box, packing, cutlass bearing, propeller, and zincs. I left the diesel in my garage but brought the Hurth transmission and mounts with me, so I could make sure everything was in position. Installing the carbon fiber shaft strut I made was surprisingly easy. I just figured out how close to the rudder I was willing to put the prop. Then I cut a slot and stuck the strut in. I clamped it so it wouldn’t fall out, but I could still alter its fore and aft angle so I could get everything aligned with the transmission. I was hoping for a 15-degree down angle but when all was said and done I was at  16.3 degrees. Oh well, onward.

I made the carbon fiber shaft strut purely as an experiment. I am curious to see how it holds up, and if there are any electrolysis effects. It would have been so much easier to have purchased one from Buck Algonquin. I’ve always thought saildrives should be made out of composites. Alas.

6/14/2015  Solitaire is back in her slip now. I have recently started work at another company so progress will slow down a bit. The good news is several of my coworkers have at least some interest in undersea exploration, and the talent to be of great help. In case you haven’t guessed its coffee break time 🙂

9/15/2015 Solitaire has a propulsion system again! I was able to run the diesel in gear for a couple of hours over the weekend and it went very smoothly. Vibration was minimal, and apart from needing a better intake silencer I was left with little to complain about. Here are a few pictures of the installation process.

And a video of the Kubota diesel during one of the test runs.

And last but not least, How many licks does it take to get to the center of a Tootsie Pop? Three! This also happens to be the number of licks with a sledge hammer it takes to get to the center of a Volvo 110S saildrive with electrolysis damage. I never liked Tootsie Pops. They are the Turducken of sweets. Can’t abide Candy Corns either. They may go ok in coffee though……

Volvo 110S Saildrive Disassembled

Volvo 110S Saildrive Exploded View

If I have omitted anything you desperately need to know email me