caulking alternatives

Do any of you woodie's know of a modern elastomeric substitute for wood hulls. There must be a modern equivelent to oakum or hemp caulking for restoring wood hulls. I figure somebody has figured out some find of flexible oooz to put in there! If a guy restored a wood hull (I'm talking workboats here) it would be nice to put her in the water and not have to pump her out for a week till she swelled back up! any Idea's or am I dreaming?
8Knots

 

Do not use 5200, if you plan on keping this boat, and doing the future work yourself. First thing you need to do is to establish if your boat is just leaking just because of seams opening up from drying out. Many reasons for leaking can be fasteners are bad or aged, bad sections in the planks, at the frame areas, and some may be just loose from broken frames and caulking becoming of age. We have used tar as a substitute for the short term, till the good planks swell up. Bottom paints will be removed at the time of swellling, to expose bare wood, and worm problems at that time, though.

 

You are not dreaming, but unfortunately caulking does more than just keep the water out. In the hands of a good caulker, the oakum or cotton or whatever adds considerably to the rigidity of the hull. Poorly done, uneven caulking can cause damage by overstressing fastenings; conversely, a wizard with the mallet can subtly change the shape of a hull to correct the sheer of a hull suffering from a hogged keel. So, no, you shouldn't do without caulking on a boat that was designed for it. You can, however, substitute some modern goop (I'd suggest 3M's 4200 compound) for the traditional putty over the seams. She'll still have to take up when re-launched, but leakage should be considerably less while doing so.

Oyster's right about 5200 compound - it is wonderful stuff as long as you don't expect to remove it in your lifetime. That stuff sticks like stink to a skunk!

 

Thanks my friends: I know of a few old wood tugs up here. The one I'm in love with has been dry for several years. 70 LOA with 4" fir over 6" x 8" Oak sawn frames. She has had fresh (snow melt) in her belly for a long time. she would have to be covered and really dried out before a real hull restore could be undertaken I think! if I get silly enough to take her on would this be a plan of attack?
1) dry and remove old caulk, refasten and replace plank as required
2)re-caulk (oakum) I have read Chappele's take on caulking
3) skim coat seams with 4200
4) sand and paint
5) recover from weeks under a big hull
The seams at the face are about .5-.625" wide fastened with iron square shank 7" boat nails
Do you think the fresh water will permanently damage the structure? How far should that ice pick go before it's a deal breaker?
thanks guys 8Knots

 

Corking Good and Bad

MMD is correct in that a good corking/caulking job tightens up a wood hull. It is interesting to be around a new build as the corkers are working on her. You can actually hear the change in the planking as the hull tightens up.
Corking is not just to keep the water out of a traditional carvel planked wood hull but to stiffen the fabric of the hull.

If you are up in Alaska and are serious about rehabbing a wood tug, you better have some deep pockets and lots 'o time.

NOT that it can't be done but if nothing else I like to be objective about these things.

Big planks, timbers, need big tools and strong backs.
Ingenuity, inventiveness and patience are watchwords here people.

Depending on the condition you could be looking at 1000 man hours of labor alone. A good sized wood shop with appropriate sized tools. For instance a 28 inch or bigger bandsaor, a couple of 1/2 drill motors, lots of clamps and lots of tooling etc...

Say away from the ***miracle goops*** ain't no such thing as a miracle in wooden shipwrighting just a lot of hard work but worth it when it comes out right.

PS: Chappelle was a good historian but he was no shipwright.

Look at my albums on Imagestation for some views of shipwrighting and shipwrights tools.

 

Nice of you to drop in, Dave. Good to have you here.

 

Oh I been around but didn't have anything to add...to busy larnin' stuff.

 

Thanks Dave and MMD for the words. I didn't have the nerve to say that. HEHE Until people get involved into a project like this, it is very hard to understand some of the reasoning of proper technigues it takes to fix it right. Dollars signs seem to dictate fixes. 5200 is not the way, but is promoted as a seal for time by magazines and neighbors. ;,}

 

Thanks

Yes all points taken! I realize that she would have to be the love of your life. taking the title would be more like a sentance than an asset! But like most I have more time than money and a family to take care of so the "good deals" appeal to me sometimes tho it's not really. There was a 117' tug for sale up here a while back for 75K the cost of repowering her would have crippled me for life I think.....2 1700hp enterprise diesels w/ direct reverse. 16,000 gal of fuel. Cool boat, good price, but we all know why
I agree on the mystery goo I was just hoping. I am handy enough with real tools to do the work. My dad tought me well! We have been trying to bring him out of the 18th century for years.
Thanks again to all 8
P.S. Don't hold back Oyster we are all good friends with the same disease

 

There are syntetic caulks that work fine. They need to be prepped and primed properly. A MOST IMPORTANT thing is that they do not take the place of cotton or oakum. These are for locking the planking into a structural panel. A carvel planked boat with a sealing compound only will be loose and structurally unsound. Also, if you find an older boat with salt water use that need complete recaulking, it may also need refastening. Check for fastener fatigue and corrosion.