Daggerboard Damage
Moderators: Tim Bosma, Tom Elsen
Daggerboard Damage
I just hauled my 7.9 last week to paint the bottom. When the Daggerboard was fully visable, I noticed a 6" long by .5" deep gash in the trailing edge of the board just where it exits the trunk. about an inch or so extends into the trunk. Has anyone else had this problem and if so what caused it? The boat has been trailer sailed all its life and the daggerboard is only extended while sailing. Also, there have not been any hard hits to the bottom of the board.
Scott Awalt
Sugar Magnolia
#253
Sugar Magnolia
#253
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Steve Bowen
- Posts: 13
- Joined: Thu May 15, 2003 6:01 pm
- Location: Gloucester Pt. VA
I've repaired damage in this area more than once. I don't think it takes a particularly hard grounding to have the potential for damage, and it may not be the initial hit that does it, since the top of the board is fully seated in its "socket" when it's all the way down. If you're still bouncing along the bottom with any forward speed as you start to crank up, the board is hanging loose in the trunk and can cock back and crunch the trailing edge much more easily.
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LarryE-old
- Posts: 233
- Joined: Fri Jun 27, 2003 12:06 pm
grounding
Had this problem six weeks ago. Ran aground at 5 knots in soft sand. When we pulled the board out it looked like someone took a bite out of the trailing edge. Repaired with West, good as new.
Purr-Fect
262
262
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Scott Ross
- Posts: 16
- Joined: Sun Jan 19, 2003 12:38 am
- Location: Beverly, Massachusetts
We experienced the exact same damage after snagging a lobster pot doing 6 knots upwind during a race. It took us a few minutes to untangle ourselves and sail away. The repair bill for that one was big.
Now when we race, the crew member sitting most forward on the rail is responsible for calling lobster buoys.
Now when we race, the crew member sitting most forward on the rail is responsible for calling lobster buoys.
SAWALT,
I believe the old forums had a considerable amount of advice on this topic with several approaches to accessing the keel depending on available equipment. I had extensive leading edge and trailing edge cracks after I acquired my boat. I do not trailer but my boat stands are short (so not much keel exposed when on the hard), so I had the boat hanging high enough in the crane at the marina so the keel was dropped down all the way and I repaired what was accessable below the hull. Then, I lifted the keel partially out the top with a tackle (used a 2 ton come-along) suspended from the marina crane. You must, you MUST have enough wide spackling knives or similar to guide / deliver the Delrin slides at the top of the keel past the edge of the cabin top, otherwise you'll tear those out of the top of the keel and make alot more work - and that area doesn't repair easily. I used sufficient strong line woven around the top lifting bracket and left the keel tang pinned to attach to the tackle (probably the weak link and needs careful attention). Only needed to expose 12 - 18 inches or so of the top of the keel above the cabin to get to what I couldn't reach from below.
I repaired the cracks themselves by grinding the cracks wider, and drilling holes in from the sides where there was delamination. I used WEST System epoxy, injected unthickened into the drilled holes and used thickened epoxy to fill the cracks. The repair has held up fine except where damaged again by a grounding. I repaired those areas the same way, this time used the marina crane to hold the 2-ton come-along - completed the whole process in 6-8 hours.
This way there is no reason to completely pull the keel completely out.
Remember, the keel is heavy (600 pounds) and your lifting apparatus must be safe - if the keel breaks loose severe injury can occur to any body parts in the way. If in doubt hire a marina with the equipment but supervise the shimming of the delrin slides and slowly lift past the edge of the cabin top - otherwise they be ripped out of the keel - even the back slide looks like it will clear but it can still get hung up.
Old forums recommended sealing any cracks on the top of the keel with silicone sealant - such as around the stainless steel tang.
Greg
#433
I believe the old forums had a considerable amount of advice on this topic with several approaches to accessing the keel depending on available equipment. I had extensive leading edge and trailing edge cracks after I acquired my boat. I do not trailer but my boat stands are short (so not much keel exposed when on the hard), so I had the boat hanging high enough in the crane at the marina so the keel was dropped down all the way and I repaired what was accessable below the hull. Then, I lifted the keel partially out the top with a tackle (used a 2 ton come-along) suspended from the marina crane. You must, you MUST have enough wide spackling knives or similar to guide / deliver the Delrin slides at the top of the keel past the edge of the cabin top, otherwise you'll tear those out of the top of the keel and make alot more work - and that area doesn't repair easily. I used sufficient strong line woven around the top lifting bracket and left the keel tang pinned to attach to the tackle (probably the weak link and needs careful attention). Only needed to expose 12 - 18 inches or so of the top of the keel above the cabin to get to what I couldn't reach from below.
I repaired the cracks themselves by grinding the cracks wider, and drilling holes in from the sides where there was delamination. I used WEST System epoxy, injected unthickened into the drilled holes and used thickened epoxy to fill the cracks. The repair has held up fine except where damaged again by a grounding. I repaired those areas the same way, this time used the marina crane to hold the 2-ton come-along - completed the whole process in 6-8 hours.
This way there is no reason to completely pull the keel completely out.
Remember, the keel is heavy (600 pounds) and your lifting apparatus must be safe - if the keel breaks loose severe injury can occur to any body parts in the way. If in doubt hire a marina with the equipment but supervise the shimming of the delrin slides and slowly lift past the edge of the cabin top - otherwise they be ripped out of the keel - even the back slide looks like it will clear but it can still get hung up.
Old forums recommended sealing any cracks on the top of the keel with silicone sealant - such as around the stainless steel tang.
Greg
#433
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Tom Elsen
- Site Admin
- Posts: 419
- Joined: Fri Dec 20, 2002 5:42 pm
- Location: Minneapolis, MN & Chicago, IL
Board damage
Great advice Greg, especially the part about using spackling knives to 'shim' the delrin shims when the top of the board gets close to the top of the box. You'll need 6 - 8 knives. If you've got some old sail battens, you can cut some 6" pieces, sharpen the ends and use those as well.
Damage to the board is pretty common. The trailing edge often gets damage from sailing in chop with the board partially retracted.
Here is the address of the old message board:
http://www.boatsit.com/discus/messages/106/106.html
[/url]
Damage to the board is pretty common. The trailing edge often gets damage from sailing in chop with the board partially retracted.
Here is the address of the old message board:
http://www.boatsit.com/discus/messages/106/106.html
[/url]
Best wishes,
Tom
Tom
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Dave Grover
- Posts: 9
- Joined: Thu Jan 16, 2003 1:43 pm
Keel Damage
One word of caution - the responses here are very good. But:
I have repaired mine a few times and one time I used Marine Tex (excellent to work after setting up) for the aft edge damage where the keel comes through the hull. Since that repair was very hard, the next time the board got hit, the repair splintered and pieces got jammed between the keel and the trunk opening, requiring sending a diver under to free it up. Not a good scene.
The fact that the aft edge breaks away is a good thing since it takes some of the shock and gives the board somewhere to go, possibly saving damage to the trunk opening. The aft edge repair needs to be the first thing to go when you hit.
Prime Time
I have repaired mine a few times and one time I used Marine Tex (excellent to work after setting up) for the aft edge damage where the keel comes through the hull. Since that repair was very hard, the next time the board got hit, the repair splintered and pieces got jammed between the keel and the trunk opening, requiring sending a diver under to free it up. Not a good scene.
The fact that the aft edge breaks away is a good thing since it takes some of the shock and gives the board somewhere to go, possibly saving damage to the trunk opening. The aft edge repair needs to be the first thing to go when you hit.
Prime Time
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Mike Deye
in need of a new centerboard
I think that I have almost completely destroyed my centerboard. I ran aground in rock and the lead area has one keep boat. As I ran aground, the lead twisted when the boat turned and removed the entire fiberglass skin off of my keel. The keel was repaired quite a few times before and those actually were some of the only areas to hold up. Myself and the marina working on the boat has looked for replacement of the centerboard. We have contacted Tiara yachts to see if there are molds and they claimed that they have been destroyed. Has anybody ran into this problem ? Any advice on a new keel ? Thanks Mike Deye
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Tom Elsen
- Site Admin
- Posts: 419
- Joined: Fri Dec 20, 2002 5:42 pm
- Location: Minneapolis, MN & Chicago, IL
Keel
Mike
DO you have any pictures of the damage? Is the whole infrastructure of the board torqued so as to be unusable? It's certainly possible, but hard to believe, that it would be more cost effective to start over (building a new board).
DO you have any pictures of the damage? Is the whole infrastructure of the board torqued so as to be unusable? It's certainly possible, but hard to believe, that it would be more cost effective to start over (building a new board).
Best wishes,
Tom
Tom
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Mike Deye
Destoryed Daggerboard
Tom, It is in rough shape. I do have some pictures but I cant put them on here. Also, I could not email you. It is pretty bad. The bottom of the keel where the lead is, is twisted about 30 degrees. The lead itself is not damaged and can be twisted back due to only having one bolt. I would think that it may need a new bolt put in. The marina that the boat is at would like to replace the keel. The marina is well capable of repairing and building a new one but they feel it woudl be way cheaper to replace than repair. They are a first class marina and I have seen many of the projects that they do. I think that the marina and I would like to look into finding a new one or somebody who can construct one. We figured that the class website would be our start. I have contacted Mars Metal and they dont have any molds. I contacted Tiara and they told me that the molds have been destroyed for the daggerboard. Any ideas I would be interested in hearing so I can get back in action. Thanks for your help. Mike Deye.
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Bob PR
Lifting keel repairs
Hi, I'm Bob Pr., with the S2 6.7, 6.9 & 22 Class Assocn http://www.sail-s2.org , and this is my first visit to your forum.
Our website has lost some sections, unfortunately, that haven't yet been restored or I'd refer some of those to you. Those contain a lot of information also pertinent to your 7.9. I'll give you some of the points I think are most pertinent to this area. If this is already well-known to 7.9 members, my apologies for taking up space. I don't want to be a know-it-all but just want to share information that's been, for us, very slow and difficult to acquire.
Don Wennersten was the S2 company naval architect (his NA through Westlawn correspondence while working for S2) for a number of years before he left and became a dentist. The only boats that I know of that he fully designed were the S2 6.7 and later the 5.5. Arthur Edmonds, I believe was the N.A. for many of their cruising boats and G&S [Graham (also a Westlawn NA) & Schlagater] did their racing and performance cruiser lines. HOWEVER, although those contract NAs did the drawings, it was Wennersten who converted those designs into working, functional systems. G&S designed a lifting keel with a certain NACA foil -- Wennersten designed how it would be made and function.
Don Wennersten has graciously let me talk many hours with him to get information about our boats and how they were constructed -- and how to repair them. My first S2 was a "6.9" (same hull as the 6.7 but with cockpit, cabin, and sail plan emulating a 7.9 in 7/8ths scale -- that part was designed by G&S). That 6.9 had extensive damage to its bottom and both sides of its LK which I had to repair before it could be sailed.
Don Wennersten says that Bert Rutan (the aircraft designer) was very influential on Don's design of systems. Rutan had written a number of articles on epoxy and FG composites in the 1970s and Wennersten adapted a number of those to marine use -- that's especially true of our LKs and rudder blades. Don W. also wanted to make an LK that functioned somewhat like "Chinese blocks" with a very close fit.
The LKs of the 7.9, 6.7, and 6.9 are made of two lateral half symmetrical FG shells. S2 cast a lead slug with a ss tang properly positioned in it. (I believe they bent the bottom of the tang to form an "L" or "J".)
The two lateral halves were then taped together, the lead slug lowered into correct position, and then a slurry of epoxy resin mixed with two sizes of glass microspheres (aka microballoons) was poured in. When this hardened and cooled, the tape was removed and -- voila!!, the LK was finished.
Repairs or restoration should follow as closely as possible this OEM recipe.
As several earlier posters have noted, when one runs aground, the trailing edge becomes sacrificed. If the trailing edge were much stronger -- say reinforced with titanium -- a much more dfifficult to repair part of the boat would be sacrificed. And the boat and crew possibly lost?
It is also critical that two different sizes of glass microspheres be used. This is because the smaller size occupies space between the larger size. And the more space that's occupied, the less epoxy resin. And the less resin, the lower the heat when it cures.
Our class has a marine FG man who makes replacement rudder blades for us to sell to members needing one. (All 3 of our boats have kick-up rudder blades and rudder heads just like yours since Wennersten designed them all). Our builder tried to get by with just one size of glass microballoons but the heat from the curing epoxy kept warping the FG shells. So I consulted with Don Wennersten again and advised the builder to use the TWO sizes. That did the trick.
My advice is to NOT let the great marine shop build a new LK unless they are willing to make the new one exactly like the old one.
If they argue they can make a better and stronger one, I suggest you run to a shop that's more amenable.
Have whoever does your work rebuild from the shoulder and what remains of the foil on down. You can easily measure the length of the foil and since the LK is a constant shape, that becomes easy to reconstruct. In no case do you want to make the leading or trailing edges stronger or tougher -- they were designed to be sacrificial if necessary and easily repaired.
I remember thinking, as I worked on my first LK (I now have a 6.7 and repaired it, also), that 'gosh!, is this a hokey design!' and how it would be easy to make a better one. Since then, I've come to appreciate the VERY great wisdom of it.
Hope this helps.
S2 6.7, #81, "The TARDIS," Topeka, KS
Our website has lost some sections, unfortunately, that haven't yet been restored or I'd refer some of those to you. Those contain a lot of information also pertinent to your 7.9. I'll give you some of the points I think are most pertinent to this area. If this is already well-known to 7.9 members, my apologies for taking up space. I don't want to be a know-it-all but just want to share information that's been, for us, very slow and difficult to acquire.
Don Wennersten was the S2 company naval architect (his NA through Westlawn correspondence while working for S2) for a number of years before he left and became a dentist. The only boats that I know of that he fully designed were the S2 6.7 and later the 5.5. Arthur Edmonds, I believe was the N.A. for many of their cruising boats and G&S [Graham (also a Westlawn NA) & Schlagater] did their racing and performance cruiser lines. HOWEVER, although those contract NAs did the drawings, it was Wennersten who converted those designs into working, functional systems. G&S designed a lifting keel with a certain NACA foil -- Wennersten designed how it would be made and function.
Don Wennersten has graciously let me talk many hours with him to get information about our boats and how they were constructed -- and how to repair them. My first S2 was a "6.9" (same hull as the 6.7 but with cockpit, cabin, and sail plan emulating a 7.9 in 7/8ths scale -- that part was designed by G&S). That 6.9 had extensive damage to its bottom and both sides of its LK which I had to repair before it could be sailed.
Don Wennersten says that Bert Rutan (the aircraft designer) was very influential on Don's design of systems. Rutan had written a number of articles on epoxy and FG composites in the 1970s and Wennersten adapted a number of those to marine use -- that's especially true of our LKs and rudder blades. Don W. also wanted to make an LK that functioned somewhat like "Chinese blocks" with a very close fit.
The LKs of the 7.9, 6.7, and 6.9 are made of two lateral half symmetrical FG shells. S2 cast a lead slug with a ss tang properly positioned in it. (I believe they bent the bottom of the tang to form an "L" or "J".)
The two lateral halves were then taped together, the lead slug lowered into correct position, and then a slurry of epoxy resin mixed with two sizes of glass microspheres (aka microballoons) was poured in. When this hardened and cooled, the tape was removed and -- voila!!, the LK was finished.
Repairs or restoration should follow as closely as possible this OEM recipe.
As several earlier posters have noted, when one runs aground, the trailing edge becomes sacrificed. If the trailing edge were much stronger -- say reinforced with titanium -- a much more dfifficult to repair part of the boat would be sacrificed. And the boat and crew possibly lost?
It is also critical that two different sizes of glass microspheres be used. This is because the smaller size occupies space between the larger size. And the more space that's occupied, the less epoxy resin. And the less resin, the lower the heat when it cures.
Our class has a marine FG man who makes replacement rudder blades for us to sell to members needing one. (All 3 of our boats have kick-up rudder blades and rudder heads just like yours since Wennersten designed them all). Our builder tried to get by with just one size of glass microballoons but the heat from the curing epoxy kept warping the FG shells. So I consulted with Don Wennersten again and advised the builder to use the TWO sizes. That did the trick.
My advice is to NOT let the great marine shop build a new LK unless they are willing to make the new one exactly like the old one.
If they argue they can make a better and stronger one, I suggest you run to a shop that's more amenable.
Have whoever does your work rebuild from the shoulder and what remains of the foil on down. You can easily measure the length of the foil and since the LK is a constant shape, that becomes easy to reconstruct. In no case do you want to make the leading or trailing edges stronger or tougher -- they were designed to be sacrificial if necessary and easily repaired.
I remember thinking, as I worked on my first LK (I now have a 6.7 and repaired it, also), that 'gosh!, is this a hokey design!' and how it would be easy to make a better one. Since then, I've come to appreciate the VERY great wisdom of it.
Hope this helps.
S2 6.7, #81, "The TARDIS," Topeka, KS
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Mike Deye
keel repair
That is some good information to have. I will show this to the boatyard and this can be a start with some information how it was constructed. I agree that the keel should give before anything. It is much easier to replace the keel than the trunk. Repairing shark bites in the keel is really quite easy. My project now is rather difficult and this one will take alot of work. One thing that I find puzzling is that there is no replacement available. This seems like an easy problem to have for anybody with a 7.9. I think what the marina and I are looking for is somebody that has made new ones. I am surprised that an accident to this degree has not happened before. I will keep my information posted on how this was fixed and maybe we can create a source on keel repair. Thank you for everybodies help. I really appreciate it.