Keel protection

[Frank Olsen]

I'm in the process of refitting and repairing some minor damage from skipping over a submerged rock and want to add something better than the multi layers of glass cloth/epoxy that was my current keel protection, especially for beaching. The fiberglass held up fairly well but abraded away in several spots exposing raw wood. Luckily no structural damage to the keel, only to the rudder. My current moorage dries out every day and even though it's a silty bottom in still gradually erodes the epoxy glass as it settles in about 3"

I've considered:
1) extra wood strips and more glass. Cheap, easy to apply, but probably needs constant
repair after contact.
2) UHMW polyethylene. Extremely tough, slippery and anti-fouling, but, not glueable to the
epoxy, and I'm not crazy about exposed screws into the keel.
3) added strips of G-10. Very tough, glueable to epoxy, but, expensive.
4) strips of kevlar or carbon fiber cloth or combination of both.

Any other ideas, pros and cons, opinions, or comments?

Thanks,
Frank (Pahi31 "Mikyla")

[Randall S Anselmo]

Hi Frank,

I just bought a Tiki 26 that has a much degraded metal strip on the keels, and am facing the same dilemma on how to proceed. Do you have any updates on your solution, or other advice?

Thanks,
Randy



Frank Olsen said:

Thanks to all who commented. I've decided on a couple layers of Kevlar cloth tape topped off with a layer of glass. A couple layers of Kevlar; 1 layer 2" wide plus a layer 6", so to protect against the abrasion up the sides of the keel when the boat dries out and settles into the gritty mud daily, or I beach in the gravel. That will cost about $60 US for the Kevlar and less than $10 for the glass, plus epoxy. I might add an epoxy glued (no screws) sacrificial strip of wood to the keel before the Kevlar. Still pondering that.

Since the anti-fouling paint erodes off the bottem 3" off the keel, because of the daily drying, I'm going to try a couple layers of epoxy mixed with copper powder just on the bottom 3 o 4". Even as that abrades away it should stay anti-fouled. Hopefully it'll last longer than the bottom paint that only lasts a couple months at the keel.

I'm many months away from re-launch but after a year or so in the water I'll post on how well it works or doesn't.

Thanks,
Frank

[Frank Olsen]

Hi Randy,
Sorry I don't have much advice yet, I have finished the keel repair but have not re-launched. I have been also widening with new cross beams and cockpit. What I can tell you is that I did use 2 layers of kevlar and overlapped a layer of 6 oz glass. Working upside down is a pain so I coated with epoxy first and let it get sticky enough to lay in the kevlar without it falling off, this usually took a couple hours to get tacky enough to hold it up. Then I let it firm up a little before wetting out, if too early the added weight of the wetting out wanted to pull it away. That method worked good except I had to work around the support blocks holding the boat up high enough to work comfortably. This meant splices in the kevlar which is next to impossible to grind or sand without a fuzzy mess. Cutting the kevlar is tough enough, I found that laying the tape on a steel block and cutting it with a wide cold chisel and a heavy sledge hammer blow. That left a nice sharp edge that I was able to carefully splice after moving the supports. My first layer of kevlar was 2" the second was 4" and the glass layer was 6" which left a nice gradual edge that was easy to fair out. I then coated with two coats of epoxy mixed with copper powder to give a sacrificial anti-foul because of my daily tide dry out at moorage.

I chose kevlar over any extra wood or metal strips because of my paranoia with mechanical fastenings. Every option I could think of would still be sacrificial and I felt the kevlar is so tough and I could easily repair glass epoxy damage on a low tide without a haul out. I also plan to be more vigilant about avoiding rocks and reefs, unlike my last encounter which was "I'm sure we're far enough away from that reef" without checking the chart more carefully. I now have gps chart plotter onboard which probably would have helped avoided that contact.

I had many careful beachings with just the original glass taped keel with no damage at all so I'm confident with this kevlar and glass combination as far as beaching. I'm committed to re-launch spring of 2011 if my health and money holds up. I don't plan on any hard contact except for normal beaching which I'm already confident in, so probably not much more to report in the future unless I have another bout of stupidity.

Good luck,
Frank

[Ann and Neville Clement]

Hi Frank,
That sounds like a very sensible and satisfactory arrangement you have for your keels. I have noticed when Nev and I had to let Peace dry out on a beach with much shells and stones, that the keels did take quite a bit of abrasion. We rarely need to dry out in the way we live and sail Peace, so it has not much of a problem for us. We also have copper powder in the final coat of epoxy before antifoul paint was applied and we like the secure feeling that gives us. Perhaps you will find a less damaging spot to moor your boat in future with maybe mud rather than stones.
ann and Nev

[Randall S Anselmo]

Thanks very much for your reply and attention to detail. This will expose my inexperience with composites, but am I correct to assume that having the kevlar on the outside would lead to fraying/fuzz, and that's why you cover it with fiberglass?

Randy


Frank Olsen said:

Hi Randy,
Sorry I don't have much advice yet, I have finished the keel repair but have not re-launched. I have been also widening with new cross beams and cockpit. What I can tell you is that I did use 2 layers of kevlar and overlapped a layer of 6 oz glass. Working upside down is a pain so I coated with epoxy first and let it get sticky enough to lay in the kevlar without it falling off, this usually took a couple hours to get tacky enough to hold it up. Then I let it firm up a little before wetting out, if too early the added weight of the wetting out wanted to pull it away. That method worked good except I had to work around the support blocks holding the boat up high enough to work comfortably. This meant splices in the kevlar which is next to impossible to grind or sand without a fuzzy mess. Cutting the kevlar is tough enough, I found that laying the tape on a steel block and cutting it with a wide cold chisel and a heavy sledge hammer blow. That left a nice sharp edge that I was able to carefully splice after moving the supports. My first layer of kevlar was 2" the second was 4" and the glass layer was 6" which left a nice gradual edge that was easy to fair out. I then coated with two coats of epoxy mixed with copper powder to give a sacrificial anti-foul because of my daily tide dry out at moorage.

I chose kevlar over any extra wood or metal strips because of my paranoia with mechanical fastenings. Every option I could think of would still be sacrificial and I felt the kevlar is so tough and I could easily repair glass epoxy damage on a low tide without a haul out. I also plan to be more vigilant about avoiding rocks and reefs, unlike my last encounter which was "I'm sure we're far enough away from that reef" without checking the chart more carefully. I now have gps chart plotter onboard which probably would have helped avoided that contact.

I had many careful beachings with just the original glass taped keel with no damage at all so I'm confident with this kevlar and glass combination as far as beaching. I'm committed to re-launch spring of 2011 if my health and money holds up. I don't plan on any hard contact except for normal beaching which I'm already confident in, so probably not much more to report in the future unless I have another bout of stupidity.

Good luck,
Frank

[Frank Olsen]

Randy,
I glassed over for that reason of fuzz and also it made it a little easier to fair.
Frank

[Brandon Gamble]

I'm thinking of using this method with Element as it is time for her to have some keel work done (pics here) but not sure if I want to use Brass, steel, copper, or UHMW polyethylene screwed to it... which would be best? I will definitely be using the hardwood shoe method to prevent any penetration into the keel's skin. I plan to beach the boat regularly so I figure since I have the opportunity I should make her as strong as possible.




Polinesio - Tarcisio Silva said:

For my Tiki 21' Polinesio I use the bretrand's method, glueing an extra laminated keel and glassed it. Then screw and glued on a brass strip 1/8 x 3/4. So the keel skin is not affected by screws. This system perform very well since 2000, every time on the water and very many, many beaching. And sometimes grounding.
For paint the botton we beach the boat (very charged - we living aboard) and lift the hulls from the tide line using wood handspike... Nine years with no problems.
Bravo! it function pretty well.

[Randall S Anselmo]

Brandon,

I thought I had settled on the idea of a sacrificial wood shoe, but got to thinking that if it's glassed in, it's not so sacrificial, and would be quite a job to replace when the time came. I'm leaning toward adding a layer or two of 1708 (since I had ordered it before considering Kevlar), then using BudgetBoater's method of drilling larger holes into the keels, filling them with epoxy, then re-drilling smaller holes in the epoxy plugs to hold stainless steel screws that fasten a strip of UHMW poly. It seems to me that the poly would then be more truly sacrificial, and could be easily replaced using the screws, and that the wood would still be isolated from potential water intrusion. My reading on the UHMW poly is that it's really tough stuff, slick, and of course, immune to oxidation and fouling.

Randy

[Brandon Gamble]

I was thinking I'd wrap the sacrificial bit in glass separately and then glue it to the keel... More than anything else, I was thinking of that piece as being added wood that I could screw into without breaking the skin on the keel also with a Tiki 21 there isn't much wood down there to hold a screw so added wood is a plus.

[paul anderson]

i have just bought some 316 stainless strips for my tiki 26 keels.now i am wondering wether i could forego screws altogether and just drill holes in the stainless and then glue it.would that be strong enough,otherwise the method described by bertrand would be the way i would go.your thoughts are most welcome.

[Randall S Anselmo]

I'm skeptical that you would get a good bond between stainless steel and epoxy.  At very least, I would think you'd want to rough up the bonding surface of the metal for some "tooth".  You could experiment with a small piece (seems to be the usual advice from the epoxy makers) and see how it bonds.  If it doesn't, you've got your answer.  If it does bond under controlled conditions, you still have a leap of faith to get to actual working conditions at sea. 

 

I didn't get around to adding the UHMW poly to my keels before our recent trip, but the biaxial tape held up well.  It's only test came in one location where we had to tie up in some shallows, and she grounded on some scattered oysters/mud at low tide.  It just left a few scratches in the bottom paint.  I'll report back to this topic after I've added the UHMW poly this summer.

[hans boortman]

For my tiki 38 keelprotection I laid up 3 layers of about 1700 kevlar all the way from the bow to the keel  overlapping by about 180 mm,and laid up an additional layer of 1700 bi-ax on top before  the epoxy set on the kevlar,kevlar fusses up and cannot be sanded,with the bi-ax on top of kevlar you can now fair the glass,I believe that to be a bulletproof keel and stem!!!

[Pat Ross]

I am interested in adding additional collision protection to my fiberglass boat in addition to the watertight crash bulkheads and am looking for the correct Kevlar laminate to use, there is 29 and 49, then I see 1700 mentioned in this thread. 

I am also looking for the correct application technique i.e.  I understand that when used externally the Kevlar will need to be sheathed with fiberglass for several reasons. 

I am thinking about sheathing the bows of the amas and vaka internally and as well.  This would be within the watertight crash bulkhead areas.

Finally I am "Peeling" all three hulls from the waterline to the keels, then coming back with two epoxy coats.  My thinking regarding the exterior hull Kevlar/fiberglass laminate application is that these should be put on prior to the barrier coats. 

I understand this is a wood boat building site but it so happens you guys are talking about using Kevlar more than other forums.  I would appreciate comments from those who have experience with any or all of the procedures I mention above.

Thanks,

Pat

hans boortman said:

For my tiki 38 keelprotection I laid up 3 layers of about 1700 kevlar all the way from the bow to the keel  overlapping by about 180 mm,and laid up an additional layer of 1700 bi-ax on top before  the epoxy set on the kevlar,kevlar fusses up and cannot be sanded,with the bi-ax on top of kevlar you can now fair the glass,I believe that to be a bulletproof keel and stem!!!