Aqua Drives and thrust plates

Keep in mind that Bill isn’t a mechanic, or mechanical. He a thinker, contemplator, intellectual type guy.  When I tell you he thought for months and months about how to make our boat power better, it’s an understatement. He approached the problem the way he does everything, with lots of research, posting questions on internet boards for sailors and talking to factories and sailing friends.

His solution was installing a new drive train, at least that’s what they call it in a car. The stars of this show are an aqua drive, thrust plate and new propeller. New engine mounts, prop shaft, rope cutter and cutlass bearing were bit players.

New Aqua Drive replaces a single shaft

New Aqua Drive replaces  propeller shaft

Bill’s theory was this: The propeller pushes the boat, so the entire thrust pushing thirty-five thousand pounds of boat puts it pressure on the propeller shaft that goes into the transmission that in turn pushes on the engine and finally to the four engine mounts attached to the hull.   Thus, it is ultimately just the engine mounts transmitting all the thrust which pushes the boat around.

Bill decided to take all that forward force and short cut it before the transmission, putting the pressure on a very strong hull-mounted thrust plate instead. You do this by mounting an Aqua Drive (like the CV joint on your car’s axles) that installs on a custom made heavy duty aluminum plate which is mounted using exceptionally strong custom made aluminum brackets attached to special on- site fabricated fiberglass cleats under the floor. Yes, I am sure that I’ve lost you at this point but I assure you he thought this through.

fiberglass cleats and aluminum brackets

fiberglass cleats and aluminum brackets

I understand the theory, I am mechanical and I bought on to this refit. I examined the fabulous fiberglass work Christopher did each day.  The custom aluminum thrust plate and mounting brackets, that were template and measured by Lindsay, are impressive, thick and strong. What a great job. If you have to overbuild a boat, I say do it there, it’s what will be pushing the boat. I get this part. Great job Bill and Maritime Solutions.

old hefty propeller

old hefty propeller

Now, here is my dilemma, why is the new propeller so puny? I don’t understand how it is better, why it will make our boat power faster. The original propeller was thick and strong, all the qualities we just built into the new thrust plate. But, without a great propeller creating the force on the plate, we won’t go anywhere. It’s physics says Bill, says our contractor, Lindsay, says the propeller’s Canadian manufacturer, West by Northwest.  Better design.  More “cupping”.

new puny prop

new puny prop and rope cutter 


Lindsay, Maritime Solutions

So we did a test run and Bill says we increased speed by more than a knot.  That’s substantial but there were only 15 knot winds and no waves or swell fighting us, so how can we really tell.  This may be the only time in my life that I can’t wait to go out in the ocean with big seas. I want to fully appreciate our new investment and I’ll be happy when Bill says, ‘I told you so.’ Happy we spent our retirement income wisely.

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