Marinette Boat Forum

My 37 does have about 3" of insulation on all engine hatches.

Roge

I have lived with a pair of Perkins 6-354 diesels for 15 years now, and I am familiar with Cummins engines because there is one in my 91 Dodge pickup, which I purchased new. Both engines are excellent. The Cummins has trucked me around for 1/4M miles with almost no service. The Perkins have a similar record.

Each Perkins with its tranny weighs about 1000 lbs, and so having the diesels changes the character of the boat considerably. Think crewboat. It won't act like a Marinette unless you can keep the added weight down -- and it is hard to compete with the engines that came with the boat.

My cabin floor has been raised a few inches to accommodate the Perkins, which are 6-cylinder and taller of course than a V-8. This annoys me because I am 6'3" but no one else notices.

I put sound insulation with a barrier layer (the good stuff) under the entire floor and on the bulkhead forward of the engines. This is not optional. It is still noisy but does not trouble us because we ride on the flybride or in the cockpit. Hamilton Marine has the stuff at a good price.

The Perkins are rated at 120hp continuous commercial duty at 2800 rpm and I run them at 2800 rpm just like a commercial operator would. With a clean bottom and Liz riding on the bow, I get a solid 18 knots which is both cruise and top speed. Fuel burn is almost 8 gph/side, which gives economy about the same as gas engines at the same speed. This is with the stock 1.5:1 trannys and 15 X 15 props.

Where the diesels shine is at low speeds. Brevard county is full of idle zones, supposedly protecting the manatees, and fuel burn at low speeds is too small to measure easily. Carbureted engines are terrible at low speeds, and I have often wondered if it would make sense to use a "rich" control like on airplanes to lean them out when called for. I would go for fuel injection if at all possible.

The fuel return can be incorporated into the fuel sender, to avoid reworking the tank. Senders with a fuel return are available. Or, you could go with a separate day tank that you can fill either manually or automatically from the large tanks, like on a crewboat.

I like the diesels because they sound like a real boat to me, and because there is little fire hazard. If I had it to do over, it would be to get more power -- mine are naturally aspirated and this block can be had in turbocharged form. Lighter engines would be nice. Diesel was a wonderful choice back when diesel fuel was much cheaper than petrol, but those days are long gone.

Probably the best of all would be new Chysler engines with better manifolds and fuel injection.

I have written enough here that everyone will expect a recommendation. OK, here it is: Do what you want, it's a damn hobby, after all.

jsutton, you'd be better off just buying my boat. Seriously I think that for what you would spend converting you'd be better off to just purchase a boat that has what you are looking for.

http://sandusky.craigslist.org/boa/4945946407.html

Sean

Well, much time has passed. I was planning on working on the boat all summer but was not able to start work until the last few weeks. I have ripped out the floor and gutted the bilge. I am in the process of removing the nasty tar gue and silver paint (what a mess!). I am afraid this job has turned into an all out restoration process.

I ordered two Diamond 370s each paired with ZF 220A 1.235 gears. I will be working with Seaboard Marine (Tony Athens) throughout the re-power process.

I ordered a custom welded hardtop for over the cockpit and another for over the fly-bridge. The hardtop on the fly-bridge will collapse backward onto the cockpit hardtop for trailing. The idea is to be able to fully enclose both areas when desired.

I will be blasting the entire thing down to the aluminum and doing both topside and bottom-side paint jobs before it goes back in the water.

First question: Once I remove all this nasty tar and paint in the bilge, is there any reason that I need to paint the aluminum? I will be putting this thing in Florida for a few months out of the year so it has to be ready for the salt. My understanding is that the extruded aluminum is all 6016 and the sheet material is all 5386 (designed for marine/salt use). If I can leave it raw and not have to worry about all the prep and painting I will be one step closer to the end. I am a bit afraid that this paint job will be very challenging and may result flaking paint someday. Any thoughts?

I don't have a painted bilge and it seems to be just fine. It does see rainwater that gets in occasionally, but there is little or no salt and I have seen no corrosion.

Top builders like Burger paint the interiors of their hulls with white enamel, which looks stunning and is very easy to work in. It might be worth doing while the engines and trannys are out.

The original primer on my topsides is still holding most places, and yours might be fine. It is a lot less work to sand and add another coat, than it is to etch and build up from bare metal. The factory did a good job of it, don't waste it.

I sand the factory paint aggressively (36 grit) until the primer starts to show, then paint with two-part epoxy high-build primer, then sand again with 180 or so, then roll on three coats of Petit Easypoxy, first coat very thin, last coat with some extra thinner and tipped, sanding lightly between coats. This yields a job that is serviceable and looks great from ten or fifteen feet away, which is appropriate for a boat. Some others on this site are accomplished painters who can do a professional job with the tough paints (Awlgrip) and a finish that bears close scrutiny. If that's what you want, ignore this paragraph!

I think I will bypass painting the bilge if I can get it to come clean and look half way decent with an acid wash. I figure after that I can keep it clean with something like purple de-greaser carefully applied to the subject surfaces only.

I'm taking her down to bare aluminum wish me luck!

Thanks for the sound barrier advice I am checking it out at Hamilton Marine.

Anyone know the weight difference (roughly) between a 32' Fisherman and a 32" fly-bridge sedan? Thought it was 1,500 lbs or so but cannot verify as of yet.

"jsutton" I'm taking her down to bare aluminum wish me luck!

From my own experience and observation, Marinette did a good job of laying down a barrier/primer coat over the aluminum. So you may want to consider leaving it alone. On the other hand, the paint they used for topcoat was terrible, chalking after only a few years service.

If you do go to the trouble of going to bare aluminum, I'll repeat here what you may have read so often on the forum and that is to make sure you get a primer coat on the bare surface within hours (not days). My boat suffered when the paint crew violated this rule - paint lifted in all the bared spots while the paint over the factory primer held fast. Arrrgh.

Finally, the listed weight of the 32 FB sedan was around 10,500 lbs.

Thanks for the paint/primer advice.

I have seen the 10.5k number for the sedan. I guess I should have asked what the fisherman weighs. I rolled across the scall at almost 14.5k with almost empty tanks and a 3k trailer. 14.5k is much more than I expected. I had the 360's in at the time, but these should hardly weigh more than 318's. I was a bit baffled.