42 with 310 hp. 671 n's

[Scott Mather]

I have seen a couple of 42' sport fish with 310 hp. 671 N's.
Does anyone have any first hand experience with this package.
What cruise speed is realistic?

We have 37' 1978 hat with the 671 n's and cruise at 16 to 17 knots.
42 is only 2000 lbs heavier with same approx beam and spread over 5 more feet on water line, seams it would still provide 16 to 17 knot cruise speed.

We are looking at upgrading to 42 from 37, boat spends most of time at dock so cruise speed is not big deal, and 671's are simple to work on and maintain.

Thanks,

 

[nor'easter]

I don't know first hand. I seem to remember a couple of 42s on the market with 300hp cummins 903s that report a 16k cruise, FWIW. I also had a dock neighbor in the past that ran 300hp 903s in a 42 Uniflite and reportes similar #s, even though he ran the boat at 10-11k for economy over longer distances. At that rating, I imagine those 671s will be around a long time. Hope it helps.

 

[SKYCHENEY]

I think the 16kt cruise sounds about right. Our 43DC had the same power and it cruised at about 15kts.

 

[Boatsb]

I have a 41c series 1 with 8v53's at 280 HP. I get 16K cruise and 19-20 on the pins. The boat weighs 33,000 dry.

 

[jim rosenthal]

Scott, that is about right. Between the fact that the engines don't put out a great deal of power, and their weight, the boat won't go real fast. If you are comfortable with a 16kt cruise (which is just above planing on that boat, I think) they will last you a long time. 310hp is not much to ask of a 6-71. I had a 44' Striker, which is a larger boat but weighed about the same, and that was about the cruise speed. I think one time I saw 20kts with a clean bottom, fresh engines, and no weight to speak of.

Now, if you really wanted to have fun, Cummins M11s would fit in there real nice.....just a thought...