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cordova
07-22-2006, 01:24 PM
Just a quick question...If your stringers are somewhat rotted, but not the whole way through, and they are dried out can they be repaired by re-enforcing them but screwing plywood against them and fiberglassing over them? Or do they need to be replaced? The boat I'm working on is a mid-70s thundercraft. The rott seems to be localized beneath the ski locker and doesn't run the length of the boat. Thanks!

Boozer
07-22-2006, 01:27 PM
Just a quick question...If your stringers are somewhat rotted, but not the whole way through, and they are dried out can they be repaired by re-enforcing them but screwing plywood against them and fiberglassing over them? Or do they need to be replaced? The boat I'm working on is a mid-70s thundercraft. The rott seems to be localized beneath the ski locker and doesn't run the length of the boat. Thanks!
If the doctor diagnosed you with cancer would you feel comfortable putting a band aid over the tumor? Probably not.

JetBoatRich
07-22-2006, 02:46 PM
Pull the engine and replace them :rolleyes: once the load of the engine is out, they may find them loose as well :mad:
I replaced mine in the jetboat last summer :rolleyes:

AZKC
07-22-2006, 03:08 PM
Pull the engine and replace them :rolleyes: one the load of the engine is out, you may them loose as well :mad:
Huh, No Habla :crossx:

a catered life
07-22-2006, 03:36 PM
tell us where your located that might help?

cordova
07-22-2006, 11:54 PM
it's an i/o (inboard outboard i think the abreviation is) so the engine doesn't rest on the stringers. I spoke to another boat enthuist(s/p) and he mentioned that the whole stringers need to be replaced and I fear he is right. The whole matter behind this boat is it was my Opa's(dutch grandfather) boat and he died 10 years ago this year, and he was very very close to me so i it really hold a huge sentimental value to me. I am only 22 and can't afford to get it replaced professionally. I was planning to do it myself with the help of my father(the fiberglass expert). I just want to get it on the water. The engine is mechanically sound and all that keps it from the water is this problem....by the way..you guys are increadibly fast posters. I'm on several other forums that don't move as half as fast as this one. Believe me it's a good thing. Thanks again for all the positive feed back

YeLLowBoaT
07-22-2006, 11:57 PM
where are you located? some of us might be able to help for a beer or 2

cordova
07-23-2006, 12:05 AM
Mississauga ontario (a sub-urb of toronto). I noticed you guys seem to be like a small family. That's such a good thing to have. I post a question on 240sxforums.com (I drive a 240sx) and they flame me like crazy!!! an i've been on that forum for 5 years!!!!!!!

boater012
07-23-2006, 12:44 AM
I have replaced more stringers than I care to count!! Having said that, If you have never done this before, but your dad has some fiberglass experience then I would start by disassembling the interior. If you have a photgraphic memory then just bag and tag everything you remove (I.E. screws ,nuts, bolts, seats ,panels. Anything that has to come out to do the job. If you do not have a photographic memory then take a video of the disassembly of the boat. Still bag and tag everything that you remove. I would take 15-20 pictures or more with a decent digital camera for reassembly. (makes it much easier to remember what goes where).
Once the interior is out figure out what length, width and height the current stringers are. Make a cardboard pattern of both the inside and outside of the stringers. (mark them port and starboard and inside and out!) Take your time and be accurate! Make lots of measurements from different reference points and take more pictures. (some with a ruler or long level to refer to later). Once you have your patterns go to your local supply house and get "clean" doug fir. (clean meaning no knot holes). Cedar works as well.
Take your patterns and make your new stringers to replace the old ones.
At this point you should not have cut the old stringers out yet! test fit the "new" stringers next to the old ones, make any adjustments to your new stringers that are needed before cutting out the old ones. Now that you have the "new" ones ready to go your going to want to get ahold of a decent quality "sawzall". Get yourself some long 12" or so blades to cut them with, with a course tooth on them. Drill a hole as close to the hull as possible through the stringer at one end. (BE VERY CAREFUL NOT TO CUT THE HULL) Insert your blade in the hole you just cut.
Slowly and VERY carefully cut the old stringers fiberglass away from the hull. Once the old stringers are both cut out spend some time and clean up your mess from the cutting. Your going to want to get a small 4" grinder with a course 36 or so grit paper disc on it. BE CAREFUL NOT TO CUT TO DEEP. Grind the area down where the stringers came out of and make it as clean as possible.
Vaccum the whole boat out and hose the area you have just cleaned down to get any dust that may be trapped in the glass. Vacuum again to remove any water. Make sure the hull is very dry before continuing to the next step. If in doubt let it dry out for 12 or so hours in the sun! Your going to want to get some fiberglass cloth and resin with hardener. I always start with a heavy woven roving for the first layer then follow it up with finer finish cloth. Before mixing any resin or cutting any cloth place your new stringers into place and make several marks as to where they will be located in the boat,(refering to your measurements and pictures of course, a permanant marker works well).
I always make a pattern with my cloth for the sizes that I want before i get out the resin. Cut all the pieces of roving and cloth to size and dry test fit them to the ares they will go. (again mark them with your marker) You can even make sections of the stringers if they are too long. Mark the stringer and the cloth for what you want. I always try to go 6" away from the stringer on either side. you want to make your pieces go 6" out the side up over and 6" out the other side. Making sire it fits tightly against the stringer.

boater012
07-23-2006, 01:15 AM
Once you have all of your pieces cut and marked you are almost ready to go. Your going to want to get some good Thickener for the resin you have chosen. Make yourself a batch of resin with the proper ratio fo the hardener for it. Start with one stringer and lay down some of your resin with thickener in the boat where the stringer will go. push the stringer into place and make sire it is in teh right spot (per the marks you made earlier to the hull with your marker).
Place some weight on the stringer to keep it firmly in place! Clean up the excess resin and filler that has squeezed out the sides. Being careful not to disturb the placement of the stringer. Repeat this step on the other side. If you feel you can't do the second one without bumping the other one then wait until the resin is dried to do the second one. Once the two stringers are bonded to the hull, You can start laying the roving in place I prefer to lay out a large piece of some formica to work on, Something hard and NOT porous. (spelling) Lay the first piece of roving down and soak it with some mixed up resin and hardener. I forgot to mention you want to get a slow hardener to give you more time to work if you are using epoxy resin.
Once you have your first piece of roving all soaked with resin, lay it into place and work it into the corners with a putty knife (preferably plastic). and make sure it has plenty of resin on it to stay. (It may help it stay if you prebend the roving around the stringer BEFORE you resin it up). "Sometimes" a couple of really small stainless phillips head screws have to be put it in to hold it in the corners. Continue working with the roving until one stringer is completed. IF you are using polyester resin you HAVE to do all of your glass work at the same time or you have clean it extremely well and even sand between coats ( it gets waxy when it dries and the next coat wont stick to it).
I prefer west systems epoxy but it is pricey. Smiths epoxy works just as well and is less expensive, but sometimes hard to find. If you are using epoxy you can do it in stages. Once the roving is completed you can move on to the finish cloth. I prefer to use a fine cloth since this is what you will see when you are done. Repeat as with the roving but be extra careful not to overwork the cloth or it won't look great when you are done. Let the new stringers dry for a few days in the sun. When you start the reassembly process you will undoubtedly have to drill holes through the new stringers for seats, engine mounts and tanks. Whenever you drill a hole in the stringer, Make sure that you drill it one size over sized.
Once the hole is drilled and the mess cleaned up you can coat the inside of the hole with epoxy or resin as used in the replacement. ( I prefer to use a piece of copper tubing or stainless tubing if you can find it that is the appropriate size for the bolt, and epoxy it in to the stringer, for the bolt to go through.) You can still refer back to your old stringers OR your patterns for where the bolt holes go. Reassemble the boat and go have fun!!!
David Baker Any questions feel free to call me! 1-310-388-7296
P.S. if I made any spelling errors it is 2:15 A.M. give me a break guys!