Balsa core repair in hull

Just purchased hull number 3623, balsa core in hull is saturated with water. It came through hole where boom crutch is stepped. Am considering doing repair myself, what can I expect? Anything specific to watch out for other than the obvious core damage? Any suggestions would be helpful.

Comments

Ditto in the boom crutch with 3586.

Ditto in the boom crutch with 3586. I found it (the balsa) saturated this weekend after spending time fighting spiders, wasps and beer cans in a half hearted attempt to clean the boat up before a day sail with friends. The resident gurus at my club advised flipping the boat, drilling small holes in all the soft areas to drain the goop out, sucking anything else out, and letting it dry, then injecting "GET ROT" into the areas effected. Reglassing around the deck boom crutch socket and then fabricating a wooden pad to cover the hole and drilling a hole in the wooden pad to insert the boom crutch. The other option suggested was to call Flying Scot and have them perform the repairs. Others suggested selling the boat as is and advising the prospective new owner of the softness and trading up to a newer stiffer boat. I will flip, drip and glass. [xx(]

I have experience with wet core.

I have experience with wet core. When I surveyed the boat for sale by U. of TX I found #177 had a patch of spongy hull on the stbd side about 5 feet long. The rest of her was sound (but ugly). Since the outer hull integrity means the most and keeps the water out I knew she'd be ok. I at first thought perhaps the core was just wet and could be repaired by drying completely and administering with a liberal dose of Clear Penetrating Epoxy, but after taking several "core samples" I found the core to be black with decay. #1-Purchase the small book: Sailboat Hull and Deck Repair by Don Casey It covers all of the above and below in detail SO,,brace her up on the ground to hold the shape, cut the inner deck laminations off with a 4" grinder and fiberglass cutting disc, scrape out the rotted balsa core, let the surfaces dry good, and grind off the remaining glass edges around the area using a 5" sander/grinder with a 36 grit pad. Meantime order 1/2" balsa blocks from Flying Scot,Inc. or 1/2" vertical grain balsa contour sheets from Defender. Purchase a good Marine Epoxy and silica filler (West System or System Three are good for this job)Fiberglass cloth(12 oz)(don't use mat with epoxy), Woven Roving(a heavy duty fiberglass cloth)and a bunch of stirring tools, cups, and assorted things you'll need to spread the epoxy onto the surfaces. Safety equipment is a must: eyeprotection, earplugs, breathing protection (I used a good cartridge type filter mask since I knew I'd be using solvents in there also.) Flying Scot,Inc. was kind enough to send to me a diagram and helpful instructions on how the F/S is to be repaired. It shows the layers of Glass and Core relationship. The whole process is not that hard really, however, it is not all peaches and cream either. You get dirty, muscle aches from laying in/on/around tight places at times. The actual glass/core replacement only took four or five days worth of work for me. (The whole project of making the boat healthy and cosmetizing her took me a year with my work schedule.) I learned a lot about working with epoxy and can honestly say I did a good Bristol job. She sails good and looks good. If you like working with tools and your hands and want to save some money give it a go. If you don't have the time take her to the factory. [8D]

See this web site : www3.

See this web site : www3.sympatico.ca/dompou It shows how bad things can go when you replace balsa core wood Call me if you want more details Robert Montreal

quote:[i]Originally posted by Bruce177[/i] [br]I have experienc

quote:
[i]Originally posted by Bruce177[/i] [br]I have experience with wet core. When I surveyed the boat for sale by U. of TX I found #177 had a patch of spongy hull on the stbd side about 5 feet long. The rest of her was sound (but ugly). Since the outer hull integrity means the most and keeps the water out I knew she'd be ok. I at first thought perhaps the core was just wet and could be repaired by drying completely and administering with a liberal dose of Clear Penetrating Epoxy, but after taking several "core samples" I found the core to be black with decay. #1-Purchase the small book: Sailboat Hull and Deck Repair by Don Casey It covers all of the above and below in detail SO,,brace her up on the ground to hold the shape, cut the inner deck laminations off with a 4" grinder and fiberglass cutting disc, scrape out the rotted balsa core, let the surfaces dry good, and grind off the remaining glass edges around the area using a 5" sander/grinder with a 36 grit pad. Meantime order 1/2" balsa blocks from Flying Scot,Inc. or 1/2" vertical grain balsa contour sheets from Defender. Purchase a good Marine Epoxy and silica filler (West System or System Three are good for this job)Fiberglass cloth(12 oz)(don't use mat with epoxy), Woven Roving(a heavy duty fiberglass cloth)and a bunch of stirring tools, cups, and assorted things you'll need to spread the epoxy onto the surfaces. Safety equipment is a must: eyeprotection, earplugs, breathing protection (I used a good cartridge type filter mask since I knew I'd be using solvents in there also.) Flying Scot,Inc. was kind enough to send to me a diagram and helpful instructions on how the F/S is to be repaired. It shows the layers of Glass and Core relationship. The whole process is not that hard really, however, it is not all peaches and cream either. You get dirty, muscle aches from laying in/on/around tight places at times. The actual glass/core replacement only took four or five days worth of work for me. (The whole project of making the boat healthy and cosmetizing her took me a year with my work schedule.) I learned a lot about working with epoxy and can honestly say I did a good Bristol job. She sails good and looks good. If you like working with tools and your hands and want to save some money give it a go. If you don't have the time take her to the factory. [8D]
Bruce 177: I read Don Casey's book on Hull and deck repair. I think I have a good concept of the project. However, I am uncertain about one basic issue: Eric Allman at Flying Scot,Inc. insists that the only way to repair the problem is to invert the boat. I suppose that would entail cutting into the hull from the outside. The alternative is to keep the boat as is and work from the floor of the cockpit. Which is best? Am I missing something?

NO NO NO NO N.

NO NO NO NO N. Do Not Turn the boat upside down to fix/replace the core. First you must block the boat in such a way that it is being held in the stock shape and secure enough that you can work on it. Second, only repair a small area at a time I recommend 6: to 12" strips running across the boat. This will allow you to use your repair to stiffen the surrounding area. If you attempt to do do all the core at once you risk locvking in a hull shape that's not fair. A Very Good Book on this is "The Gougeon Brother Book on Boatbuilding".

I totally agree with FS4049.

I totally agree with FS4049. Blocking the hull shape without the original mold makes it harder to keep the original hull shape so smaller section repair is best. Put her on the ground, keel down, brace up the stern and sides with wood blocks until she's very stable. Periodically check the blocking for slackness and adjust.

Agreed with the keeping upright for HULL repair.

Agreed with the keeping upright for HULL repair. Perhaps Eric was referring to deck core repair, then it would make sense to flip to keep the epoxy draining toward the outer skin. Dennis Dieball, in Toledo OH did my hull core repair much the way stated in the above listing. Looks like a good framework to build on.... Also if you don't want to get into your own repair and live near Toledo/Detroit, Dennis is a good guy to use if he is still doing this stuff.

I am currently doing similar repairs to #812.

I am currently doing similar repairs to #812. I have two sections on the port side of the trunk about 1 suare foot each where the interior layer (the floor you walk on) of glass was delaminated from the balsa. After removing the interior layer I found the balsa to be damp but no rot and still securely bonded to the hull, so I put a dehumidifier in the boat to dry it thoroughly and then glassed it again. I probably could have drilled some holes and injected some epoxy or git rot or something but since I race the boat I do not want to increase its weight. The boat was weighed about 6 months ago and was about 22 lbs overwieght, not sure how much was due to the wet core. If anything I am hoping to lose some weight with the repairs but definently do not want to gain weight. The starbord side has a larger area of delamination adjacent to the trunk and extending outward about 12 inches on average. The paint on the floor was worn way years ago so the balsa core is visible throught the translucent layer of glass. The balsa does not appear to be darker which would be rot so maybe it will be in similar shape as the port side, I will know more this week after I open it up. The trunk itself is very solid with basically no flexing when sailing to windward or if you push against it with as much leg force as possible. The boat is on the trailer and I have tapped the effected areas from underneath and do not come up with the dull thud that I get from the interior floor areas. I am thinking that is due to the balsa still be bonded to the hull securely, we will see. When examining the interior floor (which is easy to do with no paint remaining) there are probably hundreds of spots where the 24 oz. cloth has airpockets which may have been from the cloth not being completed wetted out with resin when the boat was built. I suspect this could be a contributing factor in the delamination areas. 24 oz. cloth has a course weave and takes a bit more effort to wet it than a lighter weight cloth. It seems that boats which are kept in racing condition have higher resale value and that seems enough reason to do the repairs as the factory would do them rather than injecting the core or using a foam core etc. The other thing is I want to keep it legal from a one design standpoint.