Replacing Stringers II

So, why replace the entire stringers and not just repair them? Well, take a look-see at the picture below.



You see that pile of black stuff between the fiberglass holding the stringer in place? That ain't plywood anymore - that's mulch. Great stuff if you want to grow a garden, I suppose, but it wouldn't hold a screw or the cabin sole down to save its soul.

I now officially have two stringers replaced and I'm working on the third. I hope to have the fourth and final one in the v-berth area cut and fiberglassed in by Wednesday of this week. I want to cut the 3/4 plywood for the sole in the v-berth and have it done sometime this weekend. I'm sick of looking at bare stringers. I'm sick of walking on (tripping over) bare stringers. I want to see a nice, clean, sold-looking floor. I've made a lot of progress this week, but seeing the substrate in place will give me a solid sense of accomplishment.

One thing I've discovered about epoxy vs. polyester resin is that the epoxy takes forever to cure unless its like 70 degrees outside. Working with the epoxy is nice because you have a lot longer working time than you do with polyester. Anytime I've used polyester resin it starts to gel and get hard in just a few minutes. The other thing I like about using West System Epoxy (which isn't the outrageous price) is the ease of mixing the stuff if you use their plastic pumps. Those pumps are worth every penny of the $12 bucks they ask for them. Beats the hell out of trying to measure two parts in the correct ratio by hand. Still, the work would go a lot faster if the epoxy didn't take so long to cure. If not for that I would be done with all the stringers already. You have to cut the stringers, laminate them together and then wait. Then you get to sand them, seal them with epoxy and then wait. Then you get to set them in place with thickened epoxy and then wait. Then you get to fiberglass the stringers to the hull and then (you guessed it) ...wait. I try to keep two projects going at the same time so I can be busy with something else while the epoxy is curing, but it's not always practical. Sometimes I just have to walk off and do something else.


Considering the cost and time involved, if it isn't of structural importance, you can bet I'll be using polyester resin when I can, but I don't trust it for structural elements like stringers. It may take longer and cost more, but I want them to still be there 10 years from now.

And speaking of keeping two projects going at once, below are some pictures of other repairs and projects I've been up to.

Replace Sailboat Stringers

The whole cabin sole needs to be replaced, but before I could even think about doing that, I have to replace the rotten stringers. Though I've worked with fiberglass a lot in the past, and I don't question for a second my ability to work with wood, I've never put the two together to tackled this kind of project. I read everything on the internet I could find about replacing stringers in a sailboat, but at some point you have to stop reading and thinking, and just start doing and see what happens. Well, this is what happened.

1. First I ground out the old stringer and sanded everything to the bare fiberglass.



2. I used large popsicle sticks and some poster board to create a pattern for the new stringer.




3. I used the newly created pattern to cut a dummy stringer out of cheap 1/4 plywood, then, after ensuring it fit, I used to 1/4 plywood pattern to cut two stringer pieces out of 3/4" MDO plywood. I used West System 105 epoxy and 205 hardener to laminate the two pieces of MDO into one 1.5" stringer.



4. I rounded off the edges of the stringer, sanded it, then sealed it on 6 sides with a coat of epoxy and then sanded that.



5. I mixed some epoxy and thickened it with 405 Filleting Blend and used that to set the stringer in place and filleted the edges.




6. After the thickened epoxy set, I sanded that smooth with 100 grit sandpaper.



7. I precut all the pieces of fiberglass cloth I felt I was going to need. I cut 4 pieces of 12 oz. cloth for each side (8 in total) and 4 pieces of 6 oz. cloth to wrap over the top of the stringer.




8. I covered the stringer in epoxy then laid down two pieces of the 12 cloth on the sides, saturated that, then laid a piece of the 6 oz. cloth over the top (overlapping the 12 oz. cloth all the way to the bottom), and then repeated that operation 4 times. By my understanding that means the sides are covered in 4 layers of 12 oz. cloth and 4 layers of 6 oz. cloth.



9. Once everything set up, I sanded everything the next day.