IMPORTANT! Calling all Tiki 38 Builders & Owners
Over the last week it has come to notice that there is a potential weakness with the foremast case on the Tiki 38.
I was first made aware via an e-mail forwarded to me from Daniel Ganz on ‘Marabu’. In April he left the West Indies enroute to the Azores and was some 500 miles out when he noticed a crack in the aft end of the mast case. See the photos below.
Fearful that complete failure might result in loss of the foremast and deck he lashed everything together, turned the boat around and thankfully made it back to a safe harbour without further mishap.
What is particularly concerning about this failure is that ‘Marabu’ was only launched in 2008/2009 and so the plywood was sound without any signs of rot.
Daniel e-mailed Hanneke at JWD to tell her of the problem and to seek her advice. She replied with some recommendations which I’ll get to shortly however her e-mail also revealed that a few months previously there had been a similar failure on another Tiki 38 called “Jumpa Lagi”.
“Jumpa Lagi” is now owned by Olivier Faucon and is considerably older having been built in Brunei in 2004. In this case the failure was attributed to rot in the mast case and the photos below show what Daniel thankfully avoided.
Although of differing ages both ‘Marabu’ and “Jumpa Lagi” have been sailed extensively and, as Hanneke pointed out in her e-mail;
“The mast case is under considerable strain in steep seas sailing to windward”.
Her recommendations to Daniel were as follows;
“I think you will need to dismantle the cracked wood parts and replace them with new good quality plywood as per the original drawings. I would then suggest that the whole mastcase is strengthened with two hardwood longitudinals along the outside upper edges of the mast case, i.e. hardwood timbers of 80mm x 25mm placed vertical. These should be full length, so they sit on top of the crossbeams at front and back. In both cases the maststep has worked well for many years before failing, so the break is due to a fatigue problem. Many Tiki 38s have sailed many ocean miles without showing a problem so far. I think this strengthening is sufficient to avoid any further problems’.
Today I received an e-mail from Hanneke telling me about these failures. She is making modifications to the plans and will be sending them out to all of the Tiki 38 builders and owners that they know about.
She asked if I would assist in publicising this information as there may be some owners and builders out there who are not on the JWD database but that might read my blog.
I know that Daniel has posted about his problem on the Wharram Builders and Friends site so hopefully this important information will get out there quickly.
Needless to say I’ll be making my mast case super strong!
Neil,
The first question I would ask is.. were the two failures actually built to specification and of high quality materials? It appears to me that too many builders make serious changes to the designers plans without thinking through the possible long term issues.
But seeing as JWD has made changes I would incorporate those as the best current design. Good luck
I haven’t seen any problems with my mast case… 😉
From the begining i have been watching this piece. So far so good.
Hi Neil,
Scary stuff! Thanks for bringing the matter to the attention of the Wharram community. As it happens I have recently been thinking hard about the rig for Kira. So far I have stuck to the plans believing JWD knows best, but I am now minded to move to the “dark side” and am contemplating fitting a junk rig. An unstayed mast fitted in each hull would avoid such stresses that have been the undoing of Marabu and Jumpa Lagi. I am re-reading Practical Junk Rig, and will discuss my plans further with Sunbird Marine. I recall following a Belgian couple building a Tiki 46 a few years ago who went down the same route; I am also thinking of going to electric hybrid propusion too!
As an update, I am now on a sabbatical for the next 3 months. Kira’s starboard hull is now parked in my garden, and I am now working on the port hull. I have nearly completed fitting the lower hull panels, and will shortly start glassing. I am getting faster; it has taken me 3 weeks this time to get to the same position as it took 7 months for the first hull!
My web site is still down, but I want to use all available time to build Kira rather than fiddling about with technology.
Keep going
Adrian
My mast case has not shown a problem and now I think about it I raised the mast be 1 meter and increased the sail area of the jib and foremain accordingly – thus increasing the laoding!!
One thought comes to mind and that is if you allow the foremast to rest against the back plate, that is going to put enormous pressure on the aft mounting arms. Think of the leverage of the mast against it and the dynamic loads as you bash into the seas going up wind. So keeping the forestay tight enough to prevent this from happening is important.
Regards,
Dave
Dragon
Hi Dave good to hear from you!
Interesting though about the foremast putting pressure on the tabernacle like that, I’m glad you’ve had no problems.
Definitely something to keep a weather eye on though eh?
Hi Neil
I’m still building my tiki38 which I started many years ago. The tabernacle has made me scratch my head from the beginning and the aft end in particular has always made me think it looks like a joke. The documented failures are exactly what my common sense structural engineering insight has been telling me! It looks like it can’t work and it doesn’t. I look at this flimsy plywood box suspended in mid air, forward, with the added stresses from the jib and fore decks and compare it to the half beam that carries the aft mast. That one is built like it is part of a railway bridge. It makes no sense to me. Years ago I already heard of a case of a foremast punching its way through the tabernacle. That time it appeared to be the builders fault for using a boomed jib and bottle screws instead of the recommended shroud lashings. Lashings, screws, doesn’t matter, both can deliver tension to braking point. All that load is transferred down into the tabernacle and gets concentrated at the mounting points over the cross beams, with the added problem of a substantial lever. And two hardwood sticks glued along the outside as added strength does not convince me either. It’s a makeshift and makebelieve improvement to a poor design. I built a tiki26 over 20 years ago and the mast beam support there is standard accepted engineering, like on performance and small cats: a dolphin stay, countering the downward pressure through the dolphin striker. It’s simple, reliable and very rigid, it looks like it works and it does!
How can a flimsy three sided suspended ply box without such support be expected to perform?
I built my tabernacle to plan but closed the fore and aft ends so stuff doesn’t just fall out and I added a hardwood pad under the mast location. My intention is to fit a dolphin striker there and add a stay that runs fore and aft. I haven’t decided yet if I will attach the stay to the cross beams or the tabernacle itself.
This to me is another learning exercise. Don’t always just accept what the experts come up with, more often than not your instincts are right! I sailed professionally with a great guy who skippered a big oyster. He never took for granted what the specialists and experts declared as the best solution and the result of decades of experience: he redesigned the transom of that boat and turned it into a folding bathing platform with rotating steps, and the whole lot closes up and folds away at the push of a button. Now a showpiece for oyster marine!
He considered the counterintuitive behaviour of the jet driven Williams inflatable as “lazy engineering” and designed and made the relevant modifications to make the tender behave ” normal”.
During races the big Lewmar electric primary winches used to overheat and cut out for half h, not so useful when short tacking. He singlehandedly designed and made and fitted watercooling to those winches. Lewmar said it can’t be done. Yes it can! …..
Anyway, I’m rambling. this is in memory of Philip who died last year on passage to the Azores.
He was my friend and a great inspiration to me.
Hi Andre
Thanks for your thoughtful and interesting comments, wise words indeed and confirmation if any were needed that we builders shouldn’t be afraid of making changes to what after all are extremely personal objects.
I’ve yet to finalise my preferred method for strengthening the mast box/tabernacle but whatever I do I’ll guarantee it will be far far stronger than the Wharram design.
My condolences for the loss of your friend.
I am in proses of purchasing tiki 38 Tanoa, lying Richards bay South Africa. She suffered loss of fore mast and broken up step. Need to re- build the whole structure. Is it possible to obtain plans for improved/ strengthened step / box ? Also need proper specs for replacement masts. Any asvice would be appreciated.
Emil Gaigher