Repowering a '63 Trojan Seabreeze 3100

[mrwright]

SO ... I just bought a 63 Trojan 3100. I know that originally it had the Ford Interceptor 302 in it. Somewhere along the way, that engine was pulled and now there's nothing there. In cleaning the bilge I also removed the BW Direct Drive Tranny and I'm not sure what kind of shape it's in other than the fact that it DOES spin.

Anyway, here's the question: I have two options for my repower and I'd like your guys' thoughts on them.

A) I have a running, functional Isuzu C240 that puts out 60hp on her best day with a 2:1 transmission. This engine runs great and could easily be bolted in and I'm off and running. While I wouldn't be planing my estimations are that the boat would do around 10kts at WOT while using 1gph.

B) I have a line on a number of 350s ... one is a chris craft 350 complete with tranny for $1000 but I don't know how it runs or the hours or how long it will last, etc. etc. I think there's enough power it in to get the boat up on plane while burning around 10gph.

The boat will be mainly used for living aboard with some short crab and fishing runs. Long range cruising will be a rarity.

If you were in my situation, what would you do?

[jddens]

Welcome! A 31 foot Woodie is a lot of boat for a single 350. I'm assuming it was originally a single? I would be concerned about the 60 hp's ability to control the boat in heavy water or high winds. If it were me and I was going to have a single I would consider a big block.......you will get some much more experienced responses.....lots of knowledge on this site............John

[RWS]

Don't duplicate the often made romantic mistake of turning an old nearly worthless boat into a trailer on the water.

Especially bad with a wooden boat.

The realities of this folly will slap you in the face of reality.

Restorig this vessel for practical use is another matter, however the economics will more than likely kill the deal.

Now you know why the engines were removed and not repaired/ replaced.

RWS

[prowlersfish]

Thats a lot of boat for a single small block or tiny diesel , First the boat did not come with a ford 302 from Trojan . the 302 did not come out until 1968 . so it may have had a larger engine assuming it was a single screw . If you were to go with a 60hp diesel plan on a cruse speed of 6-7 knots as you don't want to push it past hull speed . Fuel burn on 60hp diesel is around 4 GPH at wot not 1

what speed would you be happy with ? Is the boat or was the boat a single or twin ?

[mrwright]

At any rate, the last engine in it was a single screw 302. I have no idea what was in it originally when it came from the factory. this boat has always had 1 engine.

The boat's hull is hard chined and based on the original brochure I saw it appears that by design it does plane so if I were to put an engine in, I would want it to do so.

If I went with the diesel, I guess I would be happy with around 10kts ... 6-7 is just a bit slow for me.

Keep the responses coming, this has been INCREDIBLY helpful so far!

[RWS]

Keep in mind that it's NOT the engine that moves the boat, it's the PROPELLER !

Take your time on this important decision and get all the numbers absolutely right, otherwise you will simply be flushing money, effort and time down the crapper.

RWS

[rossjo]

... by design it does plane so if I were to put an engine in, I would want it to do so.

If I went with the diesel, I guess I would be happy with around 10kts ... 6-7 is just a bit slow for me.!

Seems the decision is yours.

Do you want it to plane? If so, even the 302 that was in it probably would be marginal.

If you plan to cruise around, sleep on the hook somewhere, not go out in the ocean, and use as little fuel as possible, then put the small diesel in it and a relatively large prop. As Paul said, it won't go over 6-7knots, but that's about Hull Speed - which is the most efficient speed you can operate your boat at. The diesel is safer, and your fuel won't go bad in a few months.

Do you have a transmission that will mate to the diesel you have?

Where do you live and how do you plan to use the boat?

Are you an experienced captain? A single screw 31 is a challenge ... which can be mastered.

[mrwright]

... by design it does plane so if I were to put an engine in, I would want it to do so.

If I went with the diesel, I guess I would be happy with around 10kts ... 6-7 is just a bit slow for me.!

Seems the decision is yours.

Do you want it to plane? If so, even the 302 that was in it probably would be marginal.

If you plan to cruise around, sleep on the hook somewhere, not go out in the ocean, and use as little fuel as possible, then put the small diesel in it and a relatively large prop. As Paul said, it won't go over 6-7knots, but that's about Hull Speed - which is the most efficient speed you can operate your boat at. The diesel is safer, and your fuel won't go bad in a few months.

Do you have a transmission that will mate to the diesel you have?

Where do you live and how do you plan to use the boat?

Are you an experienced captain? A single screw 31 is a challenge ... which can be mastered.

I grew up on mostly single screw boats in the <40' category and my last boat was a single screw 30' gillnetter so i'm familiar with their quirks. I live in the Puget Sound area and that's where the boat would be used with the occasional trip to the San Juans.

The diesel has a 2:1 transmission mated to it. I have a great source for props ... and even have a 20x14 prop that would work BUT based on the shaft angle, I can't swing something that large.

I have this topic posted all over the place really do want to get as much feedback as possible before I proceed in any direction.

[Big D]

Can't really add more than has already been said; all good points above. I will say that considering future maintenance, pick something whose parts are readily available be it OEM or through reputable after market suppliers.

[rossjo]

And marinizing the Isuzu diesel is not without cost (if its not a marine version already).

Otherwise, the C240 is a pretty popular engine, found mostly in the marine world on sailboats an smaller trawlers.

[captainmaniac]

To help with your power decision, consider that the 28footer Trojan made in 1969 was powered by a single Chrysler 383 cu in engine, putting out 250 or 260 HP. It ran I believe a 12x13 prop, and would hit about 12 (just on plane) at about 2000RPM; 15 @ 2500; pushing 20 around 3000... we never really did push the old girl much beyond that.

Trying to run at 10 knots is a bad idea - the boat will be fighting to get on plane at that speed, but it's not fast enough to get up on top. You will be running bow high and stern low, and that may even be the most inneficient speed for that hull. You are just pushing water.

Hull speed is closer to 8 knots. It will take a lot less power to maintain that speed, be easier on the engine and other mechanicals, and the boat will sit flatter so you will have better visibility and control than you will at 10.

If 8 is too slow for you, forget the diesel and put something in that will crank out 250-300 hp (if the hull is waterlogged and heavy, you may need the extra oomph to get 'er up).

Note : your gillnetter probably had a full length keel and big rudder. The Trojan realistically has neither, so the single screw 'quirks' may be that much more quirky than you are used to (especially when reversing to stop or back up).

Whichever way you decide to go - good luck!

[Captain Blast Off]

I have a 1963 31 foot Seabreeze with original running gear. My boat has twin 312 ford "Y" block interceptors that put out 215 hp each. Looking at my engine installation I don't think I could run a different engine without major reengineering because of the clearance from the top of the engine to the deck. I have two side draft carbs on each engine which makes the tallest part of the motor the valve cover.

If yours is a single you may have more room over the top if your engine sits lower in the hull. My expreience with speed on this model boat is that with the twin 312"s the boat will get on plane very fast however I never do it. It's way less stressfull cruising hull speed and in my opinion easier on the hull (which is almost 50 years old) and way cheaper fuel wise.

All these guys are right; I would put the biggest V-8 you could in it just for reserve power in case you get into unexpected weather or whatever mother nature throws at you. It's just safer to have extra manuevering power. I almost never run my engines over 1'400 rpm; but if I need to they will run as hard as I want to run them.

I love my wood boat but I do have a wood maintenance project nearly every year to ensure it is in top shape.

Good luck,

Steve