Bertram31.com General Bulletin Board

Re: Shaft length

Posted By: Capt. Dave Kosh
Date: Monday, 7 March 2005, at 11:52 a.m.

In Response To: Shaft length (John Davis)

Two things. 1)If the shorter shaft was not all the way in to the coupling that's your answer. Otherwise go with the same length.
2) Read the "High Performance Shafting " section under "Boat Building Tips " at the top of the BB page. This is a must read as you should get your shafts machined with a spoon for added strength. Sounds like you have gas engines as Diesels will brake 1 3/8" shafts. Do stick with AM 22 though. You want your safety factor to be above 4.0. Your shaft/prop shop will calculate that for you based on your engine torque,HP, RPM, shaft size, Prop size etc. I'm at 4.45 and broke a 1 3/8" shaft at
3.1 safety factor. So the numbers don't lie.Get your numbers before you spend the bucks. Make sure your shaft coupling is fit and faced and when you install also make sure a dimple is drilled into the shaft at the coupling where you put the set screw. The coupling really has to be torqued down good also. Good luck. Dave K

Messages In This Thread

Shaft length
John Davis -- Monday, 7 March 2005, at 10:59 a.m.

Re: Shaft length
Capt. Dave Kosh -- Monday, 7 March 2005, at 11:52 a.m.

Re: Shaft length
Walter Kaprielian -- Monday, 7 March 2005, at 2:14 p.m.

Re: Shaft length
Paul Haggett -- Monday, 7 March 2005, at 4:17 p.m.