due to excessive rig tensioning. I tried to get to some feedback on the hull deformation with a question here last week. Unfortunately, most everyone wanted to talk about rig tension percentages and causes for weather helm (the reason I got into rig adjustment in the first place). I have dimples in my hull directly below the fore and aft shrouds. There is no actual fiberglass or core failure, just a deformation. I would like to hear from anyone who has experienced this problem and what was done to fix it. I have already hatched a plan for the fix, but would like to hear other ideas.
- Status
- Not open for further replies.
H
Henry Weber
Dimples in hull
David - I have experienced 1 inch deep dimples about 18 inches across opposite the point where the support knee bulkheads for the fore and aft lower shrouds are located. The size and depth varies with the shroud tension. As yet I have not implemented a fix. The boat is a Hunter 30 from 1977. What is your plan for a solution? Do you feel this is a significant structural danger? Also there appears to be a separation of the tabbing between the knee and hull inner surface. Henry
David - I have experienced 1 inch deep dimples about 18 inches across opposite the point where the support knee bulkheads for the fore and aft lower shrouds are located. The size and depth varies with the shroud tension. As yet I have not implemented a fix. The boat is a Hunter 30 from 1977. What is your plan for a solution? Do you feel this is a significant structural danger? Also there appears to be a separation of the tabbing between the knee and hull inner surface. Henry
D
Debra B
rig tension
Depends on the size of the rigging, but there should be some play in the rig. It should not be so tight as to deform the hull! The mast is supposed to move a little bit, not be rigid Get a rig tension guage - ask around, someone in your area may have one you can borrow.
Depends on the size of the rigging, but there should be some play in the rig. It should not be so tight as to deform the hull! The mast is supposed to move a little bit, not be rigid Get a rig tension guage - ask around, someone in your area may have one you can borrow.
D
Debra B
Weather helm
Weather helm is caused when the center of effort is to high on the mainsail. Ease the mainsheet or reef the sail. (Probably a similar affect if the genoa is too large.)
Weather helm is caused when the center of effort is to high on the mainsail. Ease the mainsheet or reef the sail. (Probably a similar affect if the genoa is too large.)
S
Skip
Dimple fix
Good grief folks, tension and lee helm were covered ad nauseum in his other post, lets try to answer his question without beating that dead horse... My $0.02: You didn't say how deep these dimples are. I'm assuming they're relatively shallow. If that's right, I would be tempted to leave them be. Anything done to "push" them back out, I would worry that they will eventually pop back in, and in doing so, slacken the rig. If they're deeper dimples, and/or you can see cracked fibers in the glass (check the inside surface carefully), I would say you need to get a professional to evaluate the damage. I suspect that the real fix is to push it back out, then add reinforcing layers of fiberglass over the area. How much and where should the reinforcing go? That's why I think a pro needs to see it.
Good grief folks, tension and lee helm were covered ad nauseum in his other post, lets try to answer his question without beating that dead horse... My $0.02: You didn't say how deep these dimples are. I'm assuming they're relatively shallow. If that's right, I would be tempted to leave them be. Anything done to "push" them back out, I would worry that they will eventually pop back in, and in doing so, slacken the rig. If they're deeper dimples, and/or you can see cracked fibers in the glass (check the inside surface carefully), I would say you need to get a professional to evaluate the damage. I suspect that the real fix is to push it back out, then add reinforcing layers of fiberglass over the area. How much and where should the reinforcing go? That's why I think a pro needs to see it.
D
David Popken
I have a plan
And that plan is to first slack fore and aft shrouds. Using a simple framing lumber jig (which I can draw for you and fax or email it to you) and a hydraulic jack, I propose to put even pressure on opposing sides of the hull at the dimple points. Carefully watching the results as I apply pressure, I hope to virtually eliminate the dimples. At that point, I plan to releive tension on the jack and see if the dimples come back. If they do not, then I shall proceed to the other two and repeat the process. If they want to return without pressure, then I will have already prepared plywood pressure blocks that can be readied with a coat of fresh resin/catalyst mix then applied to the dimple from the inside and then pressure re-applied to the back of the pressure blocks with the jack and jig. The whole assembly would then be left in place to cure. Once the jack/jig is removed, you could then add more resin/catalyst and fiberglass cloth to add strength. Part of the dimple is above the salon shelves and part of it is accessible from the storage door. Fortunately the door opening is just where the jack/jig needs to be placed. There is also the question of the chain plate knees in the case of the aft shrouds. I may need to use two jack/jig combos at once to push the kness out in concert with the rear dimples. The forward shroud dimples are much smaller and in my case the chain plates are attached to a simple fiberglass strut. I guess if I try this I should take photos and post the results.
And that plan is to first slack fore and aft shrouds. Using a simple framing lumber jig (which I can draw for you and fax or email it to you) and a hydraulic jack, I propose to put even pressure on opposing sides of the hull at the dimple points. Carefully watching the results as I apply pressure, I hope to virtually eliminate the dimples. At that point, I plan to releive tension on the jack and see if the dimples come back. If they do not, then I shall proceed to the other two and repeat the process. If they want to return without pressure, then I will have already prepared plywood pressure blocks that can be readied with a coat of fresh resin/catalyst mix then applied to the dimple from the inside and then pressure re-applied to the back of the pressure blocks with the jack and jig. The whole assembly would then be left in place to cure. Once the jack/jig is removed, you could then add more resin/catalyst and fiberglass cloth to add strength. Part of the dimple is above the salon shelves and part of it is accessible from the storage door. Fortunately the door opening is just where the jack/jig needs to be placed. There is also the question of the chain plate knees in the case of the aft shrouds. I may need to use two jack/jig combos at once to push the kness out in concert with the rear dimples. The forward shroud dimples are much smaller and in my case the chain plates are attached to a simple fiberglass strut. I guess if I try this I should take photos and post the results.
D
David Popken
Thanks Skip
Getting a pro is good advice. I am only reluctant to do so because I like to tinker and to save money as well. I have the name of a reputable repair yard and it can't hurt to check out their price.
Getting a pro is good advice. I am only reluctant to do so because I like to tinker and to save money as well. I have the name of a reputable repair yard and it can't hurt to check out their price.
B
Bob
Another technique
that might work would be to get an air mattress or inner tube behind the dimple and carefully inflate it, having someone watch on the outside. This works well in some car bodywork situations - don't know about glass. I have a feeling that when you slack things off, the hull might revert to its former curvature, at which time you could beef up the appropriate area. Sounds like you have the right idea with your plan, but it's pretty involved.
that might work would be to get an air mattress or inner tube behind the dimple and carefully inflate it, having someone watch on the outside. This works well in some car bodywork situations - don't know about glass. I have a feeling that when you slack things off, the hull might revert to its former curvature, at which time you could beef up the appropriate area. Sounds like you have the right idea with your plan, but it's pretty involved.
D
David Popken
Interesting Idea but
unfortunately the inflated inner tube would have to bear on the inside of the salon cabinetry and I don't think the cabinets would put up enough resistance. However, I could put the jack/jig on the outside of the cabinets to keep them from deforming while the tube is inflated. Food for thought. Thanks
unfortunately the inflated inner tube would have to bear on the inside of the salon cabinetry and I don't think the cabinets would put up enough resistance. However, I could put the jack/jig on the outside of the cabinets to keep them from deforming while the tube is inflated. Food for thought. Thanks
- Status
- Not open for further replies.