[ View Thread ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

Bertram31.com General Bulletin Board

Re: 3126 cats

Posted By: Vic Roy
Date: Monday, 6 February 2006, at 9:38 p.m.

In Response To: 3126 cats (john)

John, way too much power for a B31. Most of our conventional thinking is that anything over about 315-330 hp a side in diesel is a waste. The B31 shaft angle is so short and thus steep, that when the boat goes above about 32 kts it starts to nose over and gets squirrley. A fix is to install prop pockets to reduce the shaft angle, and I have seen several of these installs using Cat 3116 350's and the boat will run close to 40 kts. A very major hull mod tho.

The weight is not an issue, as the Cat 3208's that came stock in B31s in the later years as an option weigh in at 2400# with gear. The 3126's at 410 hp probably will not fit anyway without major engine box mods, they are too tall, but just way too much power for the hull.

Lots of other issues, like the 410's would probably require 7 or 8" exhausts, lots of cutouts to get air to them, shafts in the 2" range, new struts, and without prop pockets no way you could swing a big enough prop (21" dia. is about the best you can do) to put the power in the water.

Again, most of us here, and we have been all over these boats for many years with just about any repower anyone ever came up with, is that the hull speed max is about 32 KTS and 300-330 hp diesel a side is about all you can run without just wasting money and creating problems in the drive train, plumbing, fuel system, etc.

UV

Messages In This Thread

3126 cats
john -- Monday, 6 February 2006, at 8:55 p.m.
Re: 3126 cats
Tony Meola -- Monday, 6 February 2006, at 9:27 p.m.
Re: 3126 cats
Doug Crowther -- Monday, 6 February 2006, at 9:30 p.m.
Re: 3126 cats
Vic Roy -- Monday, 6 February 2006, at 9:38 p.m.
Re: 3126 cats
Bill Fuller -- Tuesday, 7 February 2006, at 9:06 a.m.
Re: 3126 cats
Vic Roy -- Tuesday, 7 February 2006, at 11:39 a.m.

[ View Thread ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

Bertram31.com General Bulletin Board is maintained by Patrick McCrary with WebBBS 5.12.