The coach for the local rowing club that my son is participating in asked me since I have built some kayaks if I could give some CPR to an old singles shell that was being thrown out by the local adult rowing club. Besides the usual stress fractues and holes that have blown out where the riggers are attached, the biggest problem seems to be that either through age or time induced stress, the hull is so soft that when you push on it, it gives about as easily as a milk jug might. I don't want to add glass to the exterior of the hull as it would be too deterimental to the hydrodynamics of the hull, so I will most likely cut large holes into the decks so I can beef it up from the inside then close the deck back in later. I am looking for inexpensive ideas as to how I can take some of the flex / give out of the hull without adding too much weight to it. I know things like carbon cloth would do it, but most likely out of the budget as we are a kid driven program with no dollars. I do have scrap glass cloth and some leftover epoxy and thought about glassing in a small piece of half round with cloth over that.
You should consider the value of your 20-30 hours of time spent to cut the deck off, stiffen the hull, replace the deck to make an old, soft single an old, kind of soft single.
By the time you finish the project, how much time could the kids have spent on the water, albeit in a soft hull?
If you really feel committed, glue (polyester, vinylester, epoxy) a thin layer of NOMEX to the inner surface of the hull, then put a really thin layer of woven glass over that.
This thread shows my age, because
when I stopped sculling in 1967, fully composite shells were not yet in use. My single was made of cedar and spruce.
If I hit a heavy board at speed, the cedar might “check”, or crack along the grain. Checks could be temporarily taped, but eventually one had to get some 4 oz glass and some epoxy (nasty stuff in those days, sensitized me for years) and do a repair.
While easily broken, wooden singles stayed stiff indefinitely with reasonable care. Kind of wish I hadn’t sold mine, but it was time to buckle down and get through graduate school.
St. Pauls School
When I visited their boat house, their coach gave me a tour of their fleet which is almost exclusively wooden hulls that they have built by a guy name King over in Vermont. Although their number one crew uses a Carbon Graphite hull, almost all of their other crews still race the wooden ones. Their coach says they are equally competetive to the composite hulls and will far outlast them in the longevity department as you have spoken to. St. Pauls is one of the premier rowing prep schools in the nation so it is interesting that they still hold to the wooden tradition.
cut it out?
my experience on trying to reinforce spongy areas has been unsat. It has worked better for me to completely cut out the damaged area and patch (I use some very light plywood for backing and feather the glass in to existing good material.) The hardest part of this repair is color matching, but if that is not a big deal this is really pretty easy and much easier than trying to bond to old, wet, delaminated surfaces to beef up existing damage.
You do need access to the back side, but you will have to do that anyway. The beckson hatch suggestion is a good one.