Building a "performance cruiser" . . . ?
 

Considering adding an older 33' Trojan 10M express. The boat presently has stock Crusader 454/350HP straight shafts. My question is this, would it be feasible to take the Crusaders out and rebuild a set of midrange torque monsters, to in essence build a performance oriented, yet somewhat economical, performance cruiser?

I had a 1995 Wellcraft 32' Martinique with 7.4L merCruiser v-drives, and the boat ran at full tilt an honest 42-44 MPH on GPS. The engines were bone stock, but I had the props worked to death.

My goal would be to set the Trojan up to run 35 knots at 3200-3400 RPMs, so the secondaries wouldn't even be open yet.

What about changing the gear ratio on the transmissions? Would changing the ratio from say 1.91 or 1.52 to a direct 1:1 accomplish the same thing?

This oughta be interesting . . .:party-smiley-004:

I have had that thought with my cruiser. Maybe drop in a couple of 540's?

Mine has a couple of velvet drive 1.88 trannies. I dunno if it would handle the torque.

With mine, I seem to pick up 3-5mph by having the bottom pressure washed.

Those bobtail Crusaders are hard to beat on price and performance for an easy drop in though.

I would think simply swapping the 1.91 gears to a direct 1:1 would make a significant difference . . . and the 72C 1:1 will definitely hold up, as most of us run them behind high horsepower/high torque TRS setups . . .

As far as a clean bottom, in the old days I had a diver come out once a month and clean the bottom when the Martinique sat in the water.

Are you really thinking about going for it?

I think it is kind of a cool idea

Those old Trojans are HEAVY and WIDE. I think the shaft angle (I don't believe they have pockets) is going to be your limiting factor here. Hard to get the efficiency when you're pushing half the horsepower toward the bottom.

I'm considering it - I have a hankering for a "big" boat again, so my dad and I are contemplating splitting something. I love the look of the old Trojan express boats, so much more elegant and timeless than the Sea Rays or Wellcraft of the same vintage. Came across a steal of a deal on a 33' 10M express, asking $13,500 obo. Running, ready to go, air, genset, the whole nine yards. I figure buy something like that for $10k, dump another $10k into it making it modern, and have a $20k boat forever.

Harry

I have a friend with a 33 bertram cruiser. repowered with merc 502s, it moves out nicely, but when you lean on it you can pretty much watch the needle on the gas gauge moving

There again, I'm not looking to build a rocket ship, just an honest 30 knot or better cruise at 3200RPM. Trying to achieve the impossible, fuel efficient speed!

to run that speed at that low rpm 632's may do it...but being realistic you can do it but with normal big blocks you are going to need to 4400-4800 wot, those hulls not to bad for speed considering.....Rob

I don't necessarily agree with needing something as large as 632's, when I was running stock 7.4L merCruiser inboards in the 32' Wellcraft, it would run just about 28-30 MPH at 3200 RPM.

I think the easiest approach would be to change gear ratio to 1:1 and see what happens from there.

If I decide to buy the boat, I'll keep you posted!