A Photo & Discussion Forum for Wharram Design Enthusiasts
This is the problem: The aft section of the boat (from aft end of keel to skeg end) seems to be distorted to the extent that there's a rise of about 30mm in the curve of the sheer line when trying to fit the aft section of the lower hull panels to the backbone. The curve of this part of the backbone is flattened by about 20mm in the centre compared to the panel. The panel doesn't fit the keel doubler and the backbone at all. Obviously not good, as the problem will make the measurements of the upper hull panels, bulkheads etc. a very tricky business and possibly even an issue when looking at the lines of the finished boat - it doesn't take much to spot a "wrong" curve. I don't think it's enough to impact the performance of the boat though.
I have included a photo of the very obvious problem - aft lower hull panel versus keel doubler!
At this stage it is not possible to check all measurements, however: the panels are spot on and every other measurement I can actually check are all within a couple of millimetres. I'm a fairly experienced boat builder and work to quite a high standard of finished work, which is not to say I don't make mistakes - everybody does - but I'm confident that all the pieces have been cut out and fixed pretty close to plan specifications. Even if you get one or two measurements wrong it would in most cases be obvious when for example connecting points for a curve. The one item I can't check other than visually, is the backbone, since both are finished and off the floor of the workshop together with the ply sheets they were measured up on (as per construction plans). The aft part does look a bit flat in the curve though, but as is drawn up from several measurement points is seems unlikely that I have somehow got it wrong to this extent.
Curiously, when fitted, the lower hull panels are overall some 20mm too long. Easy to trim off, but why? Certainly not because of not having measured and cut out the panels correctly.
The floor the lower hulls are constructed on have unfortunately been flooded three times within six weeks - up to almost half a meter over the floor (but not actually touching the ply and timber, other than stem and stern). This have ruined the floor and somewhat distorted the whole set-up. However, I have tried to re-align everything and the panels do fit reasonably well, at least from aft keel to stem. No particular problems here.
I wouldn't be building the boat if I didn't trust the Wharrams to produce reliable building plans, but I do know there are issues here and there. I just can't imagine this kind of error would not have been corrected long ago - after all, the T38 have been around for a very long time. I know that giving very accurate measurements for hull panels is not really feasible, too many factors are involved to make this possible. But what I'm experiencing would be errors, not just small variations due to the construction process. Unless other builders have had the same experience I'm inclined to discount this possibility.
This leaves me with the only possible explanation being somewhere in the build and shape of the backbone or perhaps a distortion caused by the flooding in some way I'm not aware of.
I know most of us would rather not reveal a problem like this out of fear of looking like a bumbling amateur and loosing any respect of your peers etc! But I would be grateful to hear from anybody having had similar sort of problems with a Tiki 38 build or perhaps being able to figure out what might have caused this horror of a building problem!
10 years down the track and our T38 build research brings us to this exact same point. I have now seen pictures of several builds where this clearly noticeable so can at least continue reassured I guess. I was also wondering how best to tie/blend in the upper and lower panel where they connect at bow and stern and whether that common stringer was tapered off just there...
I'm currently fitting lower hull panels on my T38 build. Check out my posts on Instagram @buildingwarrior2
I'm really enjoying the process and no major problems so far! I strongly recommend adding a Chine Stringer which is not on the plans but is mentioned in the notes.