Separate Deck From Hull

[BobBill]

I don't know of books or articles, which doesn't mean there couldn't be some.

Along the edge of the hull to deck joint there usually is an extruded piece of aluminum or plastic, often it has a rubber or PVC insert. If it has the insert, find the seam (usually at the bow or transom corners) and pry it out. Grab it with a pair of pliers and pull it the rest of the way out of the track.

Under this you'll find a few hundred screws, which will likely be stainless sheet metal flat heads. Remove all of them, then peal off the aluminum/PVC track. If you're neat about this you can reuse it or you can kink it up and buy a new one.. The deck cap/liner is typically bedded or glued down. Considering the age of the boat, it's probably butyl rubber or polyurethane. Use a stiff putty knife and lever it into the joint. I usually use a torch and heat up the knife until it's red hot and this cuts right thought the bedding material.

Now the hard part is actually lifting the cap/liner off the hull shell. It's often best to use an engine hoist, chain fall or come-a-long attached to a handy tree branch. The boat's weight will assist in pealing off the liner. Work the putty knife around until it's free, then set the cap aside.

Once it's off, you'll see the foam, which will probably smell like your ex-wife's old underwear. The foam cuts very easily with hand tools like hand saws. Hack away and remove major portions, then scrape out the rest.

Clean the edges of the hull shell and deck cap where they rest on each other and prep for re-bedding the liner back on the hull. If you want you can use new foam, but I wouldn't bother, as air chambers work just as effectively as foam filled chambers.

Par, You certainly know your stuff and are extremely helpful. And, though topic is limited in appeal, may help in this project or others.

I plan to separate the deck from the hull on a small dinghy also, and your comments are greatly appreciated.

My question concerns how one separates the upper section or decking from the hull at centerboard or dagger board case?

This boat is a doubled hulled design once popular and produced by Newport Boats (Mobjack, Kite, Pacific Cat) Pics added to clarify boat. Deck is above waterline.

Am guessing the case is somehow chemically fastened when mated internally.

And, I was thinking that replacing the foam only at high points, to assure buoyancy if totally swamped...what kind of foam is customarily used?

Refers to project in thread below here - http://www.boatdesign.net/forums/sailboats/test-experiment-29733.html

[PAR]

Your boat has a bonded deck cap to hull joint as do many small sailors. Larger craft have a bedded hull to deck joint, typically covered with an aluminum extrusion and hard fastened with sheet metal screws.

Both joints can be separated, though it's a lot easier to break open a bedded joint then a bonded one.

Bonded joints have to be carefully cut open. My tool of choice for this is a small air powered jig saw sort of tool. It has a small blade and can be steered very well in confined spaces. The idea is to imagine where the joint is bonded and split the cap from the hull.

On your boat there's more to it as the dagger case and likely other areas, mast step, transom, etc., will need special attention. How to approach this would be a "open 'er up and have a look" kind of thing. You may be able to use similar techniques from the outside or you may have to wedge the boat open as best as you can then cut from the inside.

Looking inside the deck access ports with a light and mirror, may show what you're up against. In any event, you'll have to make 'glass repairs from tears, cracks and rips during the process, which is just the nature of this type of work.

Your attempt with the surface piercing bow isn't going to do much for you on such a bluff entry boat. You need an entirely different entry for this to have any merit.

[BobBill]

Thank-you, Bill. I appreciate your advice and your time.

It is as I thought. I figured it was bonded, not "butylized."

As you stated, the joint is covered by aluminum rub rails (late model as former models were teak) with pop rivets. I bought one of those vibrating tools to open the top and will add inspection ports in appropriate areas to spy.

It was the dagger board case that had caused most concern, and will have to look to see how the maker did it. This boat was made after Brunswick took over and the firm was in trouble, so they did take shortcuts that Newport and Carter Pyle likely frowned upon.

I will do it in spring and let you know.

As to the bow. I will likely not go for the dread style, but it is a thought still. I sail in areas of significant chop, so will have to hold off on that one anyway until we get the hull solid. I realize the short hull offers little opportunity for improving the straight line motion, but will leave that to later thoughts.

Hull first, improve traveler, add longer narrower kick-up rudder, add Force 5 mast, boom and sail to fit into mast chock and step.

Force 5 sail is larger, so may go to full battens and shorten, with flat head. (Will refinish original mast and boom and set aside; original sail will patch and store - all 1973 mfgr.)

One thing, What kind of foam is typical for this application. I am guessing the foam, if any, is laid up along hull sides, with open interior stem area for draining the condensation etc.

Again, I appreciate your advice and your time.

Bob H.

[PAR]

There will be no consideration for draining condensation from the interior of the boat. The foam will be open cell polyurethane or polystyrene or something, who knows, but it's suck up moisture like a sponge. It's arrangement below the deck cap will be equally as haphazard. These two things are common problems with production boats from that era. Others will be reinforcement areas made from wood, that have rotted from the moisture collected between the deck cap and hull shell, (with no place to go). Transoms and under seats are common locations for this as, would be mast steps and other high load spots.

[BobBill]

Thanks again.

So foam is a no-no.

Any other choice, styro or similar products glued in place; or just leave it and seal it?

I had thought to put minimal flotation in bow and just forward of transom on each side - styro or some closed cell stuff. Minimal amount.

Transom on this boat is solid.

I kind of guessed the foam was a sponge. Did not like idea of redoing old errors, but am limited in knowledge there.

Bob

[PAR]

Don't bother replacing the foam. With sealed chambers, they do the same thing and can't absorb moisture, plus they can be drained.

[BobBill]

Aye. Leave it and seal it then.

Thanks.

One last question. Would you recommend "butylizing" with marine sealer at deck-to-hull joinery or bond it?

I really do not know how much the two parts contribute to rigidity, but the deck and hull joint is right-angled where they join with what appears to be the snap rivets holding the rub rail through the deck and hull into the void between them..

Interesting project this.