Legend 35.5 - Crack under compression post
- Thread starter wilburleft
- Start date
You're getting some good suggestions Wilburleft. A plate (SS or Al) over the top will do little to help, although an inverted channel section is heading in the right direction. Based on how the crack has run, it looks like the cross beam is an inverted U section with a step in the sides to support the floor. The highest bending stress in this configuration will occur along the lower edge of the sides, which is unfortunately where the hole is. Reinforcing the lower edges of the channel would be the preferred solution.
If there are no signs of deck depression under the mast step, then the easiest solution may be to slacken off the standing rigging (or unstep the mast), reroute the split loom wiring underneath the cross beam, and reinforce the lower sides of the cross beam 10cm or so either side of the hole with say 6mm thick woven cloth and epoxy. A relatively easy repair, and if it fractures, then it's time for some more serious engineering analysis.
Jan
If there are no signs of deck depression under the mast step, then the easiest solution may be to slacken off the standing rigging (or unstep the mast), reroute the split loom wiring underneath the cross beam, and reinforce the lower sides of the cross beam 10cm or so either side of the hole with say 6mm thick woven cloth and epoxy. A relatively easy repair, and if it fractures, then it's time for some more serious engineering analysis.
Jan
Thanks for the advice Jan_H. I started having doubts about the steel plate option this afternoon for various reasons. Repairing and strengthening the original design, as you suggested, is probably the best course. I will look at rerouting possibilities for the wiring that runs through the hole. Also plan to consult with and engage a marine fiberglass repair person.
Greetings all! Fiberglass folks coming today. Does anybody know if the mostly hollow fiberglass rib alone is the sole support for the compression post?
I probed with a screwdriver through the hole. There is some structure inside the rib, directly under the compression post that extends down about 10 inches from the top of the rib. But there’s empty space underneath that. I think I need one of those inspection cams to look around inside there.
But the rib below the floor definitely looks mashed down, even though the top of the rib shows no signs.
I’m thinking the new fiberglass needs to be very robust. Starting to strongly suspect over tight rigging is the cause. Need to get a rigger over for a look. The thing that contradicts that deduction is that the deck at the base of the mast, both topside and bottom, shows no signs. It looks good.
I probed with a screwdriver through the hole. There is some structure inside the rib, directly under the compression post that extends down about 10 inches from the top of the rib. But there’s empty space underneath that. I think I need one of those inspection cams to look around inside there.
But the rib below the floor definitely looks mashed down, even though the top of the rib shows no signs.
I’m thinking the new fiberglass needs to be very robust. Starting to strongly suspect over tight rigging is the cause. Need to get a rigger over for a look. The thing that contradicts that deduction is that the deck at the base of the mast, both topside and bottom, shows no signs. It looks good.