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8.1 Transmission Question

R

Right Lane

New member
New member here - "Hi" to all!

I'm spec'g a new build - a planing lobster boat design - that could be powered by diesel or gas. The 8.1 Crusaders have enough power to work and if I were to make a (gas) choice today, it would be a single 385 hp 8.1.

I didn't find the Crusader website especially helpful regards transmission choices and I wonder what the experiences and preferences are here? This is very preliminary but I'd estimate the reduction to be 1.5:1 (certainly no less than this).

I'm looking for as rugged a unit as I can hang on the back of the 8.1. The boat will be engaged in offshore cod and tuna fishing in the NW Atlantic and would probably see 800 hours/year.

I'd appreciate the sharing of any thoughts on this for my application. Thanks! RL
 
Last time I checked, the standard choices from Crusader are velvet drives and Hurth/ZFs. The early down angle (5000 series) velvet drives had issues but i don't know of any issues with the current models. The ZFs are pretty reliable and have a good track record. Keeping the oil full and clean are keys to a reliable gear.

As far as the specific style and the ratio, your builder can tell you what will fit as well as the numbers. I'd consider the required maintenance actions a key driver as you need to have easy access or it will be a PITA to service. As a backup, ask the builder for a list of owners that have the same/similar hulls as you plan to buy....most will be honest and tell you straight up if you ask.
 
I would go with the diesel. Yanmar would be my choice.

The early 5000 series had problems with the pumps. They would break the pump gear, poor design. The new liberty 5000 series have been updated to a new pump design and prove to be very reliable.
 
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