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ContinuousWave: Whaler Repairs/Mods
Re-Foaming Boston Whaler Hull
|Author||Topic: Re-Foaming Boston Whaler Hull|
posted 03-09-2004 11:01 AM ET (US)
A friend recovered a 13-foot Boston Whaler boat hull from a river. The boat was capsized. He separated the "liner" from hull and scooped out the flotaton. How can the boat be restored? Can it be re-foamed? How to re-seal boat? Thank you, Joe
posted 03-09-2004 04:19 PM ET (US)
Your friend was very stupid to pull the two decks apart. The foam was put in there under pressure to make the boat a solid piece. The only foam i know of is the two part polyeurothane (spelling)foam that you mix and then pour. it would be very difficult to refoam the whole boat. Why did your friend pull it apart anyways? Just curious.
Tightlines & Happy WHALIN'
posted 03-09-2004 04:37 PM ET (US)
It would be pretty hard to do that, only way woudl be to seal boat back together and pour polyurethane foamin a hole.
posted 03-09-2004 07:05 PM ET (US)
I haven't seen this work on the scale you want, but I have seen the following work on small repairs. I also don't know the feasability of it, either.
A friend of mine had a small BW, and cracked the hull and punctured a portion of the fiberglass. He removed a 2'x2' section of the hull, and refiberglassed it, removing the damaged foam, which was also cut into a 2' x 2' area. He left a 1 1/2" hole saw hole and then took something called Neat Stuff (or Great Stuff - Home Depot sells it in their paint department) that is Liquid Aresol Foam. He took three can's and simutaneously sprayed them into the hole. When he was done, he took a piece of pre-cut fiberlass from the hole he made (he drilled a small hole and put a toggle/butterfly bolt through it) and inserted it into the remaining hole. He then put several pieces of wood with weights to hold it into place, with weight on top of the wood.
What happened next, is that the liquid foam started to expand. The hull started to bulge in the areas around where we put the Neat Stuff liquid foam. The wetter liquid foam, as the the rest was hardening was being pushed out around the hole and the cap.
When the whole (no pun intended) dried, he cut the excess foam, sanded it down, and reglassed the boat.
Many years ago, I had a 13' Dori (a cloned Whaler). I had punctured the hull, and the foam was damaged, and eventually the water started to cause the boat to separate from the foam.
Being 14, I didn't know how to fix the thing, so I sold it someone who was going to use it as a tender for his sailboat. He told me he was going to cut off the bottom of the hull, around the Bottom Paint, and let the boat dry out. Then he was going to fiberglass the boat back together again.
Who knows, he may have drilled several small holes, and injected the Neat Stuff to rebond the hull to the foam. I don't know.
I did see my old boat, several years later, turned over, on top of the deck of this guys sailboat. So who knows... maybe he figured out a way to do something we haven't yet tried.
posted 03-10-2004 09:53 AM ET (US)
Without the continuously bonded foam interior, the laminated shells of the Boston Whaler hull and deck have insufficient strength to be much of a useful boat structure. To strengthen the hull you must either attempt to pour foam into it in a manner similar to its original construction, or you could attempt to build a stringer system.
I don't know of anyone who has done either. Perhaps your article will elicit a response. You might look at Cetacea Page 30 to see a partially reconstructed Boston Whaler boat hull. The finished boat can be seen in Cetacea Page 60, wherein some guidance as to the process is given.
posted 03-10-2004 02:18 PM ET (US)
Thank your friend for removing this trash from the river. Then, haul it to a landfill.
Just my dos centavos,
posted 03-10-2004 09:10 PM ET (US)
Before you take it to the landfill I will take it off your hands. I had a 17 and did the same thing. I added two layers of biaxial glass with vinyl ester resin on the inside from front to back and side to side. Then I added 5 stringers from front to back. Then covered with light sheet metal and poured two part foam in between stringers. Once it set I pulled the metal up as i had put plastic on one side. After that I put 1/2 inch plywood down. Glued and screwed down to the stringers and glassed to the sides. Then over the entire inside coated with sani tred rubber coating. It was a great boat and i had a great year with it. Then I relaized I liked rebuilding more than using so i sold it and that person is thrilled with it. I put a 87 75hp Mercury on it and it ran about 36-38. Now I am lookig for a piece of crap again. if anyone has a piece of junk send ma an email. Do not let anyone tell you it has not been done. It is hours of work but very possible.
posted 03-10-2004 09:50 PM ET (US)
Let's look at the economics:
A 1965 13' hull sold on eBay recently for $835. Once you subtract the materials for the restoration, and I am only guessing $200 - 300, you are looking at a gross profit of maybe $600. If you want to sell it, you would have to disclose the history. Then, there's the issue of getting a new title...
The 16/17 hull that Weaver restored sells for considerably more than a 13. That might make financial sense. But, this seems like a lot of work to save $600 on this 13', unless this is truly a hobby, as it is for Weaver.
Dos mas centavos.
posted 03-11-2004 09:20 AM ET (US)
Try multipling your restoration materials figure by 10 then you will be more in the ball park for a complete restoration of the hull.
posted 03-11-2004 09:28 AM ET (US)
All the more reason to haul it to the landfill and keep your eye out for another 13' hull on eBay that is seaworthy.
posted 03-11-2004 12:03 PM ET (US)
posted 03-11-2004 03:53 PM ET (US)
Hey guys - it is not necessarily "toast" or landfill fodder - but maybe almost.
That is, if I were wanting to take a project like this on - I would separate the two shells, CLEAN!!! up the interior surfaces, provide injection AND ejection holes in the top of the gunwales (about 2 injection and one ejection on each gunwale), spray/coat all interior surfaces with resin, reseal the joint with a good epoxy and evenly clamp the two shells together. After the joint epoxy has cured, mix and pour a good quality two-part foam into the four injection holes - until it comes out of the ejection holes. After everything is cured, the excess foam is trimmed out and those ports glassed over. It might work - but I have never had the pleasure/misery of such a task.
But the cost might be even more formidible - as there might be as much as 25 or 30 cubic feet of foam required. Two part foam is pretty spendy as I recall. ---- Jerry/Idaho
posted 03-11-2004 07:47 PM ET (US)
From what I recall from the tour of the factory that Gail and I took in 1977, and watching hull molds being mated togeather, foamed and the molds opened revealing a spanking new 17' hull, here are some engineering points to ponder:
- Both the outer hull and inner liner were still in the molds, and the molds add strength for a continuous foam pour and subsequent stress of the foam expanding. The inner mold (which the factory called the "turtle"?) was hoisted, rotated 180 degrees and dropped into the hull mold, then attached. The molds _may_ have been metal.
- The expansion rate of the foam is incredibly quick. From liquid being poured down a tunnel into the forward anchor locker, clamping of what looked like a toilet plunger on steroids in the hole...to feeling the rush of air being displaced out vent holes along the gunnel was, oh...maybe _two_ minutes, tops. And we waited around for another three before the new hull was birthed.
I noticed the ballet of three workers standing on top of the mold, first mixing with a power mixer into a 5 gallon bucket for a certain set time, then a handoff o f the mixer to someone else while the two others were doing the pour and then the mixer used some paddles to scrap the sides of the bucket. One of the guys slide the plunger down and and the two others engaged hydralic clamps. All told....about a minute. They even had blocks of wood under the forward wheels of the hull mold, to tilt the mold(s) at a certain angle to allow for the foam to flow to the stern. I'll be _that_ had to be a certain cognitive learning experience.
I asked Bob Dougherty (he was our tour director) if they ever mis-timed the mix. He said yea, once in a while they didn't get the plunger down before the mix kicked off and it took about 1/2 a day to clean up the mess. And the ambient temp and humidity were concerns during every pour.
If you do a pour, based on what I saw at the factory, you would probably do best with a slow reacting foam, and multiple pours from different locations.
Best - Don
posted 03-11-2004 11:05 PM ET (US)
From what I understand of the foaming process, if the hull and liner were not in a steel mold held together with ultra-strong clamps, the hull would explode from the rapid expansion of the foam. I'm told that it also produces quite alot of heat. If the hull isn't in a mold, it will at least crack and deform from the pressure. If you take this on, be careful.
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