Inboard SeaCrafts

[PipeDreamsMarine]

Crusader has a sweet 6.0 package rated at 375hp. Should make a nice mill for a 23.

[ONESPEED]

Crusader has a sweet 6.0 package rated at 375hp. Should make a nice mill for a 23.

Thanks for all the input guys, keep it coming. Anyone have any experience with higher horsepower plants like the one mentioned above? Do you think they would produce more speed than the 22K cruise everyone seems to get in an inboard SC 23 or is this a hull speed issue w/ the inboard 23?

[riprunner]

I run a brand new EFI 350/350HP and it cruises 22-24knots on average. I think it is more of a hull speed thing and throwing more horsepower at is isn't going to bring you to a high 20's cruise.

[ScottM]

I would be a little concerned with 375hp coming out of a 6-liter (355ci?) block. Doesn't seem like it would last as long as say a 260hp 350 block. You hear about the diesel motors being souped up and having troubles like the CAT 3208 at 435hp, so I would think the gas motors would have similar issues.

Some of it has to do with hull speed, but more of it must be related to the drag created by the running gear.

[riprunner]

ScottM, yes you are correct hull speed is not the correct term, it's the drag of the running gear/angle of the prop etc....If it were hull speed the outboard versions wouldn't be any faster.

Senator Kerry had a blue Potter hull 23 with a pair of 225 mercs and no t-top and believe me that thing did more than 30knots! He kept it at a Marina I worked at when I was younger.

[dsharp]

We took a 23' in on a trade on a larger boat about 10 years ago. It originally had a 120 hp volvo diesel inboard with a jackshaft to a sterndrive. I ran it like that for about a year in the gulf out of Freeport, tx. They run o.k. when they're light on fuel; maybe 18-20 knts. The main problem is it carries 120 gal. of fuel right in the stern. It was about 15knts full of fuel and the noise was deafening; would barely plane. Took out the deisel and put in a 454 Crusader with a 1:1 borg warner - went straight inboard. I think I've got a 14x13 3-blade on it. It planes at about 1800; cruises mid 20's at about 2800 slightly over 30 at 4300. The main problem getting speed out of a Seacraft is the weight of the hull and fuel placement. I personally prefer a heavier boat than a light flimsy one. They ride better and seem to be fairly indestructable within reason. It probably would have run a little better with a 1.5 gear to get some more prop under it; that goes back to the weight. All in all its been very comfortable for its size and low on maintenance. I was wondering if anyone had tried putting a 383 chevy in one with a 1.5 to one; it would be about 300lbs lighter;

[MarkR]

Just for comparison, I run a 1975 Sceptre inboard, V-Drive, with a 260HP, 350. The prop is 16x15 and there is a reduction, 1:1.15 I think. On my GPS I get 19knts @2800rpm cruising and 30knts, with a clean bottom, @ 4200rpm.

My fuel, 62 gallons is forward of the engine. The wieght distribution allows my boat stay flat as you run up the rpms. Unlike other I/O boats I have run, there is no real transition when the hull planes out and speed picks up fast.

[Miles Offshore]

my boat originally came from the factory with a volvo deisel but it was gone when i acquired the boat. I run a straight 1.52-1 and am turning a 16/15 lhw. Tide dependant (it was 6 knots today at cape henry) I get anywheres from 19 knots to 23 knots turning 3000/3200 rpms and burning around 9 gph with fairly light fuel. 30 gallons or so. garys boat (Knot Working with his newer 350/320?) does quite a bit better then me , maybe he will chime in- hope this helps- craig