A Photo & Discussion Forum for Wharram Design Enthusiasts
I'm taking Tsunamichaser apart this winter after five years in the water. Other than quick inspections while beached, I've never pulled her fully apart since launching. God only know how much stuff is weaseled away in the hulls! That will all need to come out before I try lugging her back to the garage! I've had the mast off once before and the forward beam off too but what lurks in the corners? I figure others might like to learn from this exercise what to not do or what to beef up. I have thousands of photos from the build so I should be able to do a pretty good before and after and maybe even point out the cause. Right off the bat one thing I've known since season one was that the oak and the epoxy I used were incompatible. I have lots of open seams where oak meets oak. It seems fine if it is oak to fir or oak to Okume plywood BUT oak to oak glued with epoxy was a no go. The other thing I've learned is that shock loaded pieces will eventually fail. I have the mast down and stripped of hardware currently as the pad eye that I attached the roller reefing too broke. The only reason the mast didn't come down was that it was backed up with a loop of Samson Braid Amsteel line. Stay Tuned
Thomas you are and were an inspiration to me during my build, your blog really helped me in the early days of the build, for that I thank you. The project you are embarking on will be a great resource on this site.
All the best paul.
Looking forward to seeing this Thomas. It's interesting what you say about oak to oak. I did a fairly serious refit on Zest when I bought her, and one of the things I found was cracking in the lamination joints of the tillers. I'm not 100% sure but they might well be oak. Oak's not oily so it shouldn't be the same problem you get with teak. In conventions builds you do have to be careful with oak though, because you can't use steel fixings. The tannic acid in the wood attacks them and the wood turns black. I wonder whether the tannic acid does something to the epoxy over a long period of time? Very odd. I'm thinking of replacing my tillers with new ones made of ash next year to avoid any recurrence. The other possibility that occurs to me is that with oak being so hard maybe the stress of any flexing all goes into the epoxy, whereas with the other types of wood they've got a tiny bit more give, to spread the load.
My tillers have been a problem since day one. Mine were built of white oak that I bought as rough stock and milled to spec. I knew about the problems before hand and researched how to deal with it and followed recommendations. Every oak to oak joint glued with epoxy whether under bending stress (Tillers) or static load (Beam Pads) has cracked. Over the years I have added bolts, glass socks and rope lashings in the tiller stress spots. Not sure what else to do but replace them with something else. I find that Tsunamichaser steering very lightly and in reality doesn't need a heavy hand to alter course even in significant wind and even a springy tiller could be fine. One thing I have learned though with these boats is to RELAX. They do well if you treat them right and go with the flow. Random Images attached cause photos are fun! 1. Tsunamichaser at the dock with my sails up. 2. Looking south down Puget Sound from the western bluff on Whidbey Island. 3. "Shop" testing the new set up for the auto helm - This is a story on it's own of how I figured out how to place the tiller unit in the cockpit while meeting the 22" requirement for placement on the tiller from the rudder head. In the picture you'll see that I'm doing pull testing with a spring scale.
Attached are three pictures of Tsunamichaser's mast showing three typical repairs; Damage by the boom jaws at the top of the mast, epoxy filler where the mast thumb (made of two pieces of oak) split and the fillet on either side had cracked due to stress and a small random ding on the mast. I sanded to bare wood where I intended to fill with epoxy, added filler and then recoated the bare wood and onto the paint. Next I will sand to prepare for painting. I found no rot which was great. I built this mast out of Sitka Spruce I ordered up in the rough. If you've never seen the video of me turning this as in lathe, here's the link http://youtu.be/RXwiursRLAA
I have now stripped Tsunamichaser of her contents and various parts. What remains is what I need to get her the boat ramp where we'll take her apart and transport her to the shop (Scott's garage) In the meanwhile I've gone through all the stuff I loaded on board over the years and sorted out what I never used. I've cleaned sails and tramps. The mast and gaff have been repaired (minimal number of dings, predictable splits in the oak) and painted. Soon the mast will be rigged again ready for installation. The forward beam and the added rear tramp beam are in the shop ready for a once over to see if there are any issues.
BEAM END ROT! Everything was well coated in epoxy BUT I had hit a lock wall one time when going out through the Hiram M. Chittenden Locks http://en.wikipedia.org/wiki/Hiram_M._Chittenden_Locks to get to Puget Sound. That cracked the beam end plywood plate ever so slightly. It also wrenched the cleat at the beam end. Water must have penetrated at the cleat bolts and beam end crack. The results after 3 years of not close enough attention is a bigger repair job. I did do some epoxy filler patching at the time but not enough and the paint and glass enclosure create an egg shell affect as Scott Veirs calls it - hard on the outside, mush on the inside.
Tricky job there Thomas,I await your solution.
my experience is, wherever there are screws or nails in the wood, there is a great danger of starting rot. if it is really necessary to use screws, i do it in the "west-system" - way.My tillers are made out of okoume-wood. this wood is very soft and lightweight. This season we had a stupid accident by trying going backwards under sails out of a box... we hit a berthed steel-ferry with the end of our tiller, the tiller broke, but its softness absorbed the shock and the rudder was ok. I did some lashings and we had two more fine sailing-days at this weekend.I think tillers and tillerbar made out of soft wood has two advantages: shock absorbing in the case of an accidend and less stress on the rudderheads and the lashingspaces because the lightweight, strong enough it is certainly.
My best wishes for your refit, I do the same at the moment ;-)
This is really interesting stuff Thomas, the sort of thing everyone should see before they build their boat!
Any where you need to put a penetration in timber for fasteners should have a thickened epoxy bush at least twice the diameter of the fastening. Time consuming yes but no rot and much stronger.
Good luck with the refit Thomas.
More parts have been pulled off of Tsunamichaser. She is truly empty now except for the minimum required to get her to the boat ramp where I'll pull her from the water. It is amazing how shallow the draft is when empty. In the mean time I have finished repairs on the forward beam. As you can see, after I cut off the rotten part of the top flange, I filled in the back area of the web with solid timber (both ends for symmetry and spliced in new short section of flange. The logic to this was that the in fill piece would tie every thing together and the wider web would resist/assist in carrying compressive loads. The last coats of epoxy are curing so the next step will be paint. As a note of interest, I have always epoxied all fastener holes on this boat. I think that there may be an issue with dissimilar hardness's that can cause problems when an item like a cleat "works" it's fasteners in the hole. Eventually something gives, in this case the wood, creating micro cracks that allow in water - just a hypothesis at the moment but the cleat on the forward beam where the rot occurred has been used in mooring the boat over the last five years.
good work Thomas.
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