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'78 Searay... cont.
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how about a few details of what your all doing to her?
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Well, the more of the rotted wood I removed, the more I found. This was the proverbial 'Can of Worms'.
...and as long as I was taking everything out, I figured I might as well build the innards to be a better fishing boat.
I raised the cockpit(deck) above the engine so there would be a larger fishing area and that made it possible to make two large fish boxes that could fit a dozen 30 lb tuna in each side.:D
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why did you opt for a plywood core?
What type of epoxy and cloth did you use?
I did a smaller version of this on my trojan 10 meter - turned out to be a lot more work, but in the end I was glad I got the experiance of working with fiberglass
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That's not wood core. It's the stringers and bulkheads. Plywood is strong and rigid and it is many times stronger than what the factory put out...but that's another story.
This isn't the first time working on boats. I've done a couple cabin/hard tops. I used Tap Plastic's marine epoxy. Been using it for almost 20 years. I tried the whole gambit of epoxies over the years and Tap Plastic has all of them beat.
I also added 12' of roving to the inner hull, then 10' for the second layer, then 8' and 6' for 4 layer under the engine for added support. All of the wood surfaces are covered in at least 2 coats on epoxy and some are covered with fiberglass cloth, depending on what the exposed surface may be exposed to.
I also din not and never would use foam in the construction. From the boats I've worked on, I consider foam the be one of the major contributors to wood failure if an water gets past any barrier coat, and believe me, few manufactures properly seal the inner surface of wood and few even try to protect whatever screw or bold holes that are used to attach anything in or on their boats.
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Looking at the cockpit deck - looks like plywood to me. Using plywood like that is not as strong as if it were on edge. Why not use an end grain balsa wood core and then fully glass it in?
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Balsa core is GREAT...IF it NEVER gets wet. I'm using 3/4" ply. The same thickness all the houses use for flooring underlayment. There's no problem with strength. I made a 2'x2' cored section/cover using that white plastic (1/2" squares) used to diffuse overhead lighting with a 1/8" plywood skin and epoxied all together. It's plenty strong but is just as heavy as the 3/4" plywood. Fiberglass/plastic(resin or epoxy) is HEAVY. It's more than double the weight of water. and probably 5 time the equal volume of wood. The glue in the wood is probably heavier than the wood. Ever feel the weight of OSB(Oriented Strand Board) or glued together wood chips. Fiberglass is glued together glass fibers. Stuff is heavy.
There are really space aged coring material and using carbon fiber as the skin...but have you ever priced the stuff. I inquired about the different new coring materials. Never got a response from any of them
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i know nothing about boats. other than painting and fiberglass , but info you've posted on your project is going into my collection of tech info. btw what size engine is that looks like a car engine rather than a marine engine.
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The vast majority of recreational marine engines are based on and taken right off the automotive assembly line.
Mine, however is a 1970-71 400 ci SBC ( smallblock Chevy). I consider it one of the best base engine to build a marine engine. I have it set up to use 87 octane (regular gas) and it has the torque of a big block (454 ci). It has around 325 HP but somewhere around 425+ ft/lbs of torque at 2500 RPM. That's a lot from a small block.
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i thought it was a sbc but i wasn't sure that's why i asked. how big is the whole boat and weight ; with the power and torque, from the sbc it should almost fly through the water. i take since you have it setup for 87oc you built the engine from the ground up ?
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Any wood base core is goingto have issues if it get wet. In housing construction the 3/4 ply is going to be supported ever 12" or 16", while the cockpit deck needs to span a much larger distances. On my 10 meter the cockpit deck had to span about 11', its 13' beam, so there would have been too much sag if I would have used plywood.
From the date on the pic it looks like this is an old project - how is the deck holding up?
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She's a 24' searay. I wanted something big enuff to go offshore to look for tuna but not so big that it would be too expensive to run. How was I supposed to know that gas would get so expensive.
Anyway, with everything I've done to the boat to make it more fishable, she tips the scales at 7600 lbs. A bit on the heavy side for it's length. The stock 260HP 5.7 only averaged 1.55 MPG. I spent the last 10 years trying to better the mileage. Even with the added 1500-2000 lbs, I'm getting 2 MPG. That's a 30% increase which isn't easy to do on a boat
