Steel boat interior - how do you attatch it to the hull?

Hi all

I have recently bought an old steel sail boat (a one-off Dutch built ketch), which needs some TLC. I plan to sandblast the interior, then coat with an epoxy paint system and finally cover that with a spray-in insulating foam. My question is, how do I start to build in the interior or, more to the point, just how and where do I attatch it? Do I glue (epoxy) directly to the hull or will this cause problems with condensation? Do I glue to bare metal or does it have to be primed? I can't find any books on this part of the building process, any one know of anyhting out there that could help me?

Much thanks,
Rich C

 

You do not glue an interior to a steel hull.

You attach cleats to the tranverse frames, and/or welded tabs. The tabs would be used where no transverse frame was convienently located.

To make the cleat/frame connection either bolt through, or probably preferably, attach to welded on threaded studds. I would seal these connection points.

I guess you could glue the cleats, but I would still incorperate mechanical fasteners. In fact, done right you can do without the glue. Come time to repair or renovate you will be happy you did.

Any of the books on steel boatbuilding that I have read go over this subject.
It basically comes down to commonsense while erring on the overbuilt side of the equation.

Hope this helped.

TGoz

 

Hey... I'm in Pa. Also.. Trying to turn my flat bottom 12 footer in to a Bass boat type thing.. Maybe you can help me?

 

Where are you at Bassmaster? I'm approx. 45 SSE of Pittsburgh.

We've been doing good recently fishing the Yough River by Layton. Mainly shore fishing, with some canoe trips here & there.

TGoz

 

Bassmaster,

I checked out the photo of your boat.

Technically, I think what you have would be called a "V-Hulled" boat.

12 foot Lowe? Correct? True flat-bottomed boats are different. They generally incorperate a squared-off bow, such as a "John Boat".

Any advice I could give you that would encourage you to go forward with your plans, I fear, would be bad advice.

I would advice leaving things as they are.
Aluminum skiffs are great boats when used for their designed purpose.

12 foot is not that big. Putting a raised forward deck/pedestal chair combo on this boat would present a number of problems.

1. Stability issues due to a large amount of high up, forward weight: you, decking, supporting structure, & chair.

2. The gunwales on this boat would need significant reinforcement to properly make a deck/topsides connection.

3. Either heavy ply or lighter, but with substantial framing & bracing, ply would need to be used.

4. The area below the seat would need heavy backing.

I'd be content to use the boat as is. If your fishing from it and catching bass that makes it a "Bass Boat" in my estimation.

Most people with experience with this boat type are gonna discourage such an attempt also.

One last thought. The resulting boat could not help but look absolutely atrocious & unseamanlike. The same boat in original form has a look of simple functional beauty.

If your close and would like a hand with bringing the boat into tip-top shape maybe we could work something out.

TGoz

 

Thanks for the tip timgoz. I'm now thinking of welding in stainless steel tabs where needed.

 

RichC,

If the hull is mild steel, which is most likely, you would be better off using mild steel for the tabs. Just clean up the damaged hull coatings & weld zones well, coat tabs and recoat cleaned areas. Your coatings should be compatible with what is already there. Consult someone who sells or make marine coatings.

Where the transverse (upright) frames are in suitable positions, I would make use of these, with or without tabs (your choice).

Your country probably has more experience and expertise in steel boats than any other country. A trip to several friendly boatbuilders would be very interseting & informative.

Remember, if welding tabs directly to the inside of the hull, the areas immediately adjacent on the hulls exterior will need cleaned (sanding-wire brushed) & recoated same as the interior.

Take care.

TGoz

 

Is reducing the chance of corrosion the reason for using mild steel is (stainless steel being a different metal)? If that is the case, should i paint the outside of my stainless steel water tanks?

 

I bought an unfinished steel boat hull many years ago, well im saying un -finished what I really men is un-started.

She was 62 foot overhaul, However I do remember the intrerior having wooden beams sunken into the foam insultaion. This resulted in a sound foundation on which to start fitting the intrerior. The wooden beams of 2x2 by2 foot were just rough cut and were every where and were surprisingly sound in the sprayed on eurothane foam.

When I finally found a suitable contracter to complete the interior it saved a lot of expense as this part of the job was already instaled.

 

Rich,

I suggested mild steel because it will be as good or better than stainless for the application, if well coated, as it should be. Probably slightly easier to drill too.

Make sure to address the bare steel in the drilled hole before attaching cleats or bulkheads.

Painting the water tanks is optional (I would think).


Jack,

Are you sure there are no mechanical attachments hidden beneath the foam?

I am a big Spray fan. Have plans for a steel Spray 28 I hope to build one day.

TGoz

 

It is possible, but I would think not probable, that they could of been held temporarily in position with glue until the foam was sprayed. Once "grided" (for want of a better word) together things would stay in thier approxamate starting positions, flexing slightly as the boat works, but never shifting significantly.

But if any of the bulkheads are to be structural, such as under a mast step, I would definetly think they would have to be mechanically attached.

Does the spray in foam seem to do a good job of locking out moisture & the attendant corrosion? I'd like to make use of it for much of the interior.

Take care.

TGoz

 

I have been researching this as well. I would look hard at the ceramic microsphere insulating paints. On metal that would give good condensayion protection. I an thinking of screwing G90 galvanized tabs on my ribs and running 6" galvanized strapping strips to use to anchor the inside skin. That would leave me with a variable space to insulate the cavity.

 

Yes, corrosion is a major consideration in steel boatbuilding. Stainless steel, because the alloy contains nickel and chrome, is a "higher" metal than mild steel, so will induce corrosion in the steel (welding a "higher" metal to the steel hull will make the steel act like zinc, protecting the stainless tabs by corroding faster itself. Not good! ). Another consideration, as timgoz said, is to be careful to grind and clean the welds and the area around thembefore recoating. Welding heat makes changes in the metal immediately around the weld, again more susceptible to corrosion. Best to use mild steel for the tabs, grind and clean surfaces before and after welding. Should be plenty of info on steel boats in your area. Your tanks are OK, I think, don't need to paint.

Good luck!

 

Steel boat interior

Hi Rich, I have a couple of opinions about the use of spray in foam insulation in a metal boat. If it were my steel boat I would stay away from spray in insulation and here's why. Once you spray the stuff in place it's practically imposible to inspect those areas that have been sealed by the foam. I would feel a lot more comfortable being able to inspect areas near the hull plating and framing to see any problems that could develope and address those issues as needed. I don't believe that you can spray foam into a hull in such a way as to completely seal it from air or water. I would use foam panels cut and placed for insulation and rely on a high quality paint system to minimize corrosion. I also feel that you should only use insulation surrounding areas that are to be habitable or have some reason to be insulated, fish holds, ice holds or cold storage ect.. I wouldn't place insulation below the waterline, adjacent to engine rooms, chain lockers or other areas that won't be temperature sensitive. If possible I would build the interior so that you can remove as much as possible to do a thorough inspection at least every couple of years. That's just my workboat point of view, regards rusty