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Rot in aft beam or build "Quality" of professional and Wharram approved builder Andy Smith

Today, much to my horror I discovered that the ply webbing of my Tiki 38´s aft beam was rotten round the hole  for beam locating pin. I could trace it back to water ingress around the insert/bushing of the beam locating beam which has not properly been embedded in epoxy. Normally this is part which should not give any word and should last forever. All which hinted my to it was a small crack in the wood around the starboard pin.

This is not only a shame for a professional builder (anybody beware if he wants to have aboat boat built by Andy Smith, the Wharram approval does not seem to help anything) but also a pain to repair.  Pretty much the one side of the beam has to be cut open and the "infected" ply webbing has to be cut out. On the port hole this has been 50 cm either side of the pin, I will then scarf new webbing and wood in. On the starboard side the plywood is only wet, has anybody got experience letting the plywood dry in situ after I have drilled a few holes in it and uncovered about 20 cm2? 

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I would contact the builder and request an entirely new beam at their cost. Worth a shot and they get the opportunity to "make it right" Sorry you are going through that.

I am not certain I quite understand where the water got in, but it sounds like you are saying that the water migrated in through the oblong hole in the beam where the locating pin passes through. I see the pictures of the rot, but not the pin hole.

Based on my experience, the pin hole on a beam is a wear area since the beam and pin move against each other. The plans make no mention of putting a bearing inside of this hole, but only insist on being well coated with epoxy and graphite powder. This means that the pin is riding on only coated end grain plywood. Over time the epoxy will be worn away which could allow water into the end grain. Without more pictures or descriptions, it sounds like this is what happened to your beam. Therefor if the builder built the boat per plans, it is possibly a design flaw.

I even had a special Delrin bushing made in order to prevent what you are sayin, the problem is that this bushing has not been glued in properly, there's had been glue gaps all over and not enough distance from the plywood, afterwards it has been painted over and cheap car body putty been used to smooth the ends off, quite a pain.
on my old boat I used the same technique and is is holding up extremely well after 12 years!

Delrin, a self-lubricating plastic, is quite difficult to glue to another substance. It can be so difficult as to cause more problems than it is worth. However, properly prepared Delrin, with the appropriate surface preparation and proper glues can be mechanically bonded to almost anything (except wood.) Bonding is not waterproofing.

This being said, if I wanted to insert a Delrin busing into a Tiki 38/46 beam, I would first double the size of the oblong hole in the beam (meaning double the size of the bushing's O.D.), then completely fill the oversize hole with thickened epoxy. After cure, I would then drill out the proper size hole for the O.D. of the bushing. This way the end grain of the plywood is completely sealed off and protected by the thickened epoxy, regardless of the bushing. Personally I would press fit the bushing into the hole in this case, not attempt to glue it, even though a good bond could be established with the cured epoxy.

With all of this said, I still do not know how the builder went about dealing with the preparation of this hole, the Delrin bushing, and subsequent bonding. Delrin is simply not a substance that is typically bonded into a hole, even if you once did it yourself.



Björn said:

I even had a special Delrin bushing made in order to prevent what you are sayin, the problem is that this bushing has not been glued in properly, there's had been glue gaps all over and not enough distance from the plywood, afterwards it has been painted over and cheap car body putty been used to smooth the ends off, quite a pain.

That's no excuse at all. If you go with professional builder is because the builder is supposed to know appropriate practical scantlings and practices even if they are not detailed in the plans. If not, then what would be the "real" difference between professional builder and home builder?

Budget Boater said:

Therefor if the builder built the boat per plans, it is possibly a design flaw.

the Delrin is not supposed to glie to the wood, the mechanical connection is made by rececces which are to be filled with thickened epoxy, if then a a distance to the wood of min 3 - 4 mm is held (after the wood is fully epoxy saturated, probably even set) and the distance between wood and Delrin is filled with thickened epoxy, this will hold perfectly well ( in another case holding over 12 years). Upon examination ai could see here that the recesses have not been filled properly and there had been a lot of void around the bushing and the gap too small. During the first fixing attempt epoxy was freely seeping out of the other side, this should not have been possible if the workmanship has not been so shoddy.

If a paid builder (of anything) makes changes that are not in the plans without approval from the plan's creator, they instantly assume all legal liability if the change results in a failure. Excuse or not, it is the reality that all builders face if they arbitrarily make unapproved changes.

Ricardo Aráoz said:

That's no excuse at all. If you go with professional builder is because the builder is supposed to know appropriate practical scantlings and practices even if they are not detailed in the plans. If not, then what would be the "real" difference between professional builder and home builder?

Budget Boater said:

Therefor if the builder built the boat per plans, it is possibly a design flaw.

Based on your concept of how it is supposed to be installed, I would agree that done properly rot in the plywood should not have occurred.

Björn said:

the Delrin is not supposed to glie to the wood, the mechanical connection is made by rececces which are to be filled with thickened epoxy, if then a a distance to the wood of min 3 - 4 mm is held (after the wood is fully epoxy saturated, probably even set) and the distance between wood and Delrin is filled with thickened epoxy, this will hold perfectly well ( in another case holding over 12 years). Upon examination ai could see here that the recesses have not been filled properly and there had been a lot of void around the bushing and the gap too small. During the first fixing attempt epoxy was freely seeping out of the other side, this should not have been possible if the workmanship has not been so shoddy.

A proper paid builder should suggest to the owner the appropriate changes, then get written consent. That's his job.

Budget Boater said:

If a paid builder (of anything) makes changes that are not in the plans without approval from the plan's creator, they instantly assume all legal liability if the change results in a failure. Excuse or not, it is the reality that all builders face if they arbitrarily make unapproved changes.

Ricardo Aráoz said:

That's no excuse at all. If you go with professional builder is because the builder is supposed to know appropriate practical scantlings and practices even if they are not detailed in the plans. If not, then what would be the "real" difference between professional builder and home builder?

Budget Boater said:

Therefor if the builder built the boat per plans, it is possibly a design flaw.

And if he cannot get consent for the changes...?

Ricardo Aráoz said:

A proper paid builder should suggest to the owner the appropriate changes, then get written consent. That's his job.

Budget Boater said:

If a paid builder (of anything) makes changes that are not in the plans without approval from the plan's creator, they instantly assume all legal liability if the change results in a failure. Excuse or not, it is the reality that all builders face if they arbitrarily make unapproved changes.

Ricardo Aráoz said:

That's no excuse at all. If you go with professional builder is because the builder is supposed to know appropriate practical scantlings and practices even if they are not detailed in the plans. If not, then what would be the "real" difference between professional builder and home builder?

Budget Boater said:

Therefor if the builder built the boat per plans, it is possibly a design flaw.

Then he has got to stick to the plans.

But, do you really think this was the case? Do you think an owner to whom you explain he'll get rot in his beams will say no? Specially considering the modifications would be unexpensive?



Budget Boater said:

And if he cannot get consent for the changes...?

Ricardo Aráoz said:

A proper paid builder should suggest to the owner the appropriate changes, then get written consent. That's his job.

Budget Boater said:

If a paid builder (of anything) makes changes that are not in the plans without approval from the plan's creator, they instantly assume all legal liability if the change results in a failure. Excuse or not, it is the reality that all builders face if they arbitrarily make unapproved changes.

Ricardo Aráoz said:

That's no excuse at all. If you go with professional builder is because the builder is supposed to know appropriate practical scantlings and practices even if they are not detailed in the plans. If not, then what would be the "real" difference between professional builder and home builder?

Budget Boater said:

Therefor if the builder built the boat per plans, it is possibly a design flaw.

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