Glassing in Hull/Keel Joint

[dschultz]

I looked at a boat recently which had had its hull to keel joint glassed in.

Does this seem like a good idea?

It may help to keep salt water away from the keel bolts, but seems a bit extreme. And this was a fresh water boat.

The owner seemed pretty sharp, so I didn't question it at the time.

Any comments, I'd be interested...

Thx

[Sea Dreaming]

What kind of boat?

[dschultz]

Sabre 38

[Don C L]

I wonder if that was done to hide some kind of damage? Was it many layers of glass? I've never seen that but there's a lot of stuff I have never seen before. The keel/hull joint will flex so that glass will show cracks too eventually... not sure what they are trying to accomplish. Makes it tougher if they ever have to drop the keel. It's no replacement for good sealant and good clean bolts... imo
Had it been sailed since the joint was glassed?

[barnakiel]

Sometimes it is glassed over. But it is a bad idea if the interface is a soft bedding.

Not sure of any benefits - if water could penetrate the ballast - stub interface, it can sure penetrate the glass - ballast interface as well.

Look at other boats of the same make - maybe it is just the way the builder made them.

b.

[dschultz]

Originally Posted by Don C L

I wonder if that was done to hide some kind of damage? Was it many layers of glass? I've never seen that but there's a lot of stuff I have never seen before. The keel/hull joint will flex so that glass will show cracks too eventually... not sure what they are trying to accomplish. Makes it tougher if they ever have to drop the keel. It's no replacement for good sealant and good clean bolts... imo
Had it been sailed since the joint was glassed?

That is pretty much what I was thinking.

I haven't seen the work. It was in the water. It was done a couple of years ago.

[UNCIVILIZED]

Actually it's pretty common. Some designs more than others, but it is done all of the time. Usually on more performance oriented boats, which are more prone to having a "smile" at the keel's leading edge, where it meets the hull/stub. The reasons behind such are so that the water flow over the boat in that area is smooth, so that kind of bonding & fairing reduces drag.

And too, you have to consider that fin keels are a lot more prone to such gaps, & subsequently having their keels bonded or re-bonded in place. Especially as their cross section is pretty narrow, relatively. So it's harder to keep them snug up against the hull, what with their narrow bolt patterns, & the keel's deep & powerful lever arm.

C&C's for example are notorious for this smile, & for owners to "glue on"/bond their keels in place. And when properly well done, it's a good system. Just not one which is seen on "standard" cruisers much. But on racers, & racer-cruisers, Definitely!

Go back & read the thread by Hooked, about the repair done to the keel sump on his Wauquiez Centurion 42, by Minaret & his crew. I can't recall with certainty if they bonded the keel in place. But doubtless there was talk of such things in the thread. And the thread's a good education into how keels are mounted, to what, & what holds them on. http://www.cruisersforum.com/forums/...ir-164093.html

[barnakiel]

OK. But these will be racers from say 70'ies. Most had stubs back then.

New boats have mostly blades and the joint is flexible.

I looked up a handful of recent designs and there was no glass over the flexi bond.

Is Sabre a blade fin ballast or is it a ballast on a grp stub?

b.

[replusted]

Uncivilized is correct. Wrapping the hull stub to ballast joint with fiberglass tape is a very common practice with boats that race. It's not a means to attach the ballast to the stub but it does offer some structural benefit. It's a proven method to fair the two parts so that water flows uninterrupted over the joint. I've done this on a few of my boats and never experienced problems. I used G-Flex epoxy and fiberglass tapes which when fully cured remains flexible and will not crack even if the keel joint flexes. G-Flex is an epoxy which is excellent at preventing moisture migration into the laminate. I spoke to the G-Flex manufacture's rep who confirmed that it was a perfect product to be used for this application. Although there is some structural benefit to the bonding method, it should only be used to fair the hull to ballast joint. It would not be too difficult to drop the keel if needed. You would just have to slit the glass at the joint with something like a Fein multimaster tool or similar. The reason many boats have a "smile" is because the owner does not regularly check the torque of their keel bolts and properly tighten them when necessary. Some boats have the forward keel bolt located directly under the mast which makes inspection and tightening impossible unless the mast is lifted up a couple of feet.

[UNCIVILIZED]

"My point exactly".

[gamayun]

I did the same thing at the keel-to-hull joint and the leading edge where it "smiled" (it looked more like a puckered pout though) when I hauled my boat this year. Nice smooth faired keel = go fast.

In my mind anyway

[Don C L]

I love learning new stuff on here!

[minaret]

I do it all the time. Not generally for fairing, as this can be done without the seam tape. I do it as a red flag on older boats. If the seam tape cracks or begins to delaminate, there IS a problem with the keel bolts. Might be they just need retorquing, but for me this is a clear indicator that the keel needs to come off, if only for inspection and rebedding. And, it's an indicator which is easily seen or felt by a diver. Generally I tape with three 10 oz boat cloth for this, in epoxy of course, following guidelines for bonding to lead.

[reed1v]

Usually fairing compound is used to smooth out fin keel/hull bumps; not fiberglassing. Fiberglassing will only add weight. Plus if you race, you want to drop the keel periodically to check bolt stress.

Suspect the boat has gone through several keel bolt changes due to either being raced hard(but its not a racing boat) or a hull imperfection that does not allow the fin to sit correctly. Or perhaps there is a crack in the hull letting water into the boat, and thus fiberglassing was an attempt to patch up this problem.

Either way, would pass on this boat if it was up to me.

[bsurvey]

typically the separation between the joint is from the adjustable back stay and or mast compression. if the boat has a stubby keel the glassing of a belt around the joint is a good idea. I did this when I bought my wylie 27. there was separation . so when I put it on the hard, I tightened the keel bolt then when around the joint with 24 once woven roving. faired it down and for the last 25 years its been fine.


if the boat does not have a stubby keel and is just attached directly to the hull, that is another matter and may involve delamination of the interior floor timbers