42c w/6-71 naturals

[Paul45c]

Anybody know cruise speed on a 70's 42c w/ 6-71 naturals? I was surprised to hear from a friend who's looking that there were any naturals. My dad had one years ago with Cummins VT903's, and I knew there were many with 6-71 turbos. My friend's no speed demon, but he'd like to know. Thanks

 

[jim rosenthal]

I didn't know they built them with naturals, either. Sounds like a 15-16kt boat.

 

[newinlet]

My 37C with 671N advertised is 18knt cruise max 21
real world 14-16 Cruise 17-19 Top end
42 should be about the same

 

[Paul45c]

My 37C with 671N advertised is 18knt cruise max 21
real world 14-16 Cruise 17-19 Top end
42 should be about the same

You really think it would be the same as a 37c? That 42 must weigh at least another 4-5k, no? My guy would probably be fine if the boat at least got up on plane and stayed there without having to be WOT. Thanks for the feedback.

-- Paul

 

[whoover]

Hello, my 42 with natural 903's runs 18 knots at 2150 rpm. I'm sure that it may be a little different with DD but it gives you and idea.

Walt Hoover

 

[bluedart73]

You really think it would be the same as a 37c? That 42 must weigh at least another 4-5k, no? My guy would probably be fine if the boat at least got up on plane and stayed there without having to be WOT. Thanks for the feedback.

-- Paul

Running them WOT should not be a problem. you are pushing out much less HP than a turbo/ large injector motor.

I think the issue is will it fall of plane in rough sea/heavy load. will the boat be a dog in with this HP?

I think it will. the worst thing is falling off plane going in a head sea.

 

[Paul45c]

Hello, my 42 with natural 903's runs 18 knots at 2150 rpm. I'm sure that it may be a little different with DD but it gives you and idea.

Walt Hoover

That's very helpful, I think. They should indeed be comparable.

-- Paul

 

[newinlet]

You really think it would be the same as a 37c? That 42 must weigh at least another 4-5k, no? My guy would probably be fine if the boat at least got up on plane and stayed there without having to be WOT. Thanks for the feedback.

-- Paul

I think its quite possible the 42 might run the same or maybe a little better with a little extra length
the 37 is 29-30K Lbs Not sure but possible