Transmission

Seeker's Allison AT545 automatic transmission came from a school bus. It provides forward, neutral, reverse, and gear reduction before power reaches the NP205 and Hundested system.

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I just passed the 1/3 mark on this thread, and man what a ride. I feel like I'm too deep into a bender where I just wanna go home and sleep it off but FOMO keeps me consuming... it's like some fucked up intellectual take on La Grande Bouffe. I wanted to read it all before posting too much but I'm actually getting queasy, so I'll take a breather to comment on how fundamentally fucked the drive system is on this ship of follies. First off, casting your own propeller blades is just plain stupid. Blade profile is the one place where driveline design strays from the realm of straightforward engineering and into the dark arts. This is possibly the very worst place to rely on intuition, where all manner of diligent engineering practices and CFD won't get you anywhere near the very expensive experience gained by the industry. Now about that bus transmission... using an automatic transmission? For the stated purpose of increased fuel economy?? In front of a CPP??? I'm at a loss for words... The idea to introduce a transfer case into this sorry mess is where it gets really wild. On some level he must understand that what he needs isn't more ratio... right? And certainly not a compounding five two to one. Phew. It is actually impressive to fuck something up so comprehensively. Most comparable attempts never make it off the blocks.

Fundamentally fucked? That's a pretty low bar for a prediction. Everything on Seeker has been fundamentally fucked according to Sailing Anarchy at one time or another.

Casting our own propeller blades wasn't stupid. It was fun. We learned how to cast some big-ass bronze blades, and they have pushed a 70-ton boat a hell of a lot farther than the people predicting their failure ever expected.

Is the drivetrain perfect? Hell no. The reduction is too low. That's why we're changing it. The Hundested variable pitch propeller works. The Cummins works. The AT545 works. The prop works. And now we're adding the NP205 transfer case to get the reduction closer to where we want it.

That's the difference between building something and being a loser sitting behind a keyboard explaining why somebody else shouldn't have built it. You build it. Try it. Break shit. Learn something. Fix it. Then go try it again.

If the objective had been to design the perfect drivetrain on paper before leaving the dock, Seeker would probably still be sitting in the front yard. Instead, we're out here using the damn thing.

Seeker Fundamentally Rocks!

Sailing Anarchy

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