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New Guy, Older Boat (Tennant Turissimo 9)

Malcolm Tennant Turissimo GBE

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#1 randii

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Posted 22 November 2018 - 09:32 AM

I had some difficulty starting an account, but the administrators and programmers fixed whatever was wrong, so here I am! I appreciate their efforts. :thumbup:

 

After years of beach cat experience, I have been looking for something a bit larger. Ian Farrier's work has impressed me for years, but I really like catamarans. After a summer of searching, I got hooked on the look and feel of Malcolm Tennant's boats, of which there aren't a ton in North America. I did some travelling to visit a few boats, and a Turissimo 9 followed me home on a trailer. 3000 miles, an international border, and a bunch of states later, I'm in Central California dusting off this classic Okoume double-diagonal epoxy classic.

 

There's minor delamination around the cockpit edge, in the carvel-bent decking, but the rest of the boat and rigging is in pretty solid shape. One of the windows leaked and has slight delamination inboard, and we got some road damage to the antifoul and fairing at the bottom of one hull, but everything else is just rejuvenation that you'd expect to need to do after rescuing a boat that spent too much time in the boat barn.

 

I'll be visiting here to read up and ask questions about the care and feeding of  wooden boats. There's just not a ton of support here stateside for plywood-built boats. Gel coat and fiberglass rule the day, and that's not what I could find in the 8-10m range of catamarans.

 

My planned usage is exploring the estuary upstream of San Francisco, and working my way out to the Bay as my bigger boat skills develop, eventually thinking about coastal cruising down California or trailering down to the Sea of Cortez and exploring Baja. These are big dreams for the future, but reality right now is repairing the scuffs and delaminations, going through the boat's systems, and getting out on the water in early 2019.

 

Thanks in arrears -- I spent no small amount of time here when I was shopping (Paxfish's Wildfire was one of the boats I visited on the other coast) and considering purchase options. Also, thanks in advance, as I know there's much more to learn.

 

Randii


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#2 MartinRF

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Posted 23 November 2018 - 08:36 AM

Epoxy only for laminating or also for sealing the wood surfaces?

 

Clear finish or painted?

 

Dagger boards and rudder blades are built how?

 

Aluminium cross beams? Sleeved?

 

How old?

 

Smaller sister: http://hem.bredband.net/b262106/

 

/Martin


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#3 ScottiE

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Posted 23 November 2018 - 03:37 PM

Welcome to the T club - Great boats!  We had a guy sail his to the Pacific and back so won't be long before San Fran Bay is holding you back and you're popping off to Hawaii!


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After a decade or so of Euphoria . . . it's time to go Ballistic!
Anthony

#4 randii

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Posted 27 November 2018 - 07:44 AM

I'm not entirely certain on what is sealed and what is not, since the boat is PPG-painted entirely on the outside and mostly on the inside, but I believe her to be epoxy-laminated and epoxy-sealed on the outer skin. She's finished clear on much of the exposed Okoume strip-walls below, with some painted surfaces between the main and mid-beam. I'm not sure how to differentiate varnish and epoxy inside?

 

Daggers are ripped/flipped/laminated wood -- likely cedar. The previous owner stripped the side of one of them in an effort to squeeze past a jam in the starboard dagger well, so I can see through the 'glass for its length. The tips have been either extended or cut about a foot up, presumably as a sacrificial 'fuse' in case of grounding. Fixing the jam properly is a planned project, then that board will get a new skin. I can't say how the rudders are built, but I'd guess them to be of similar construction. They fit a little more loosely in their cassettes than I'd like, but they work for now.

 

All cross-beams are aluminum... I haven't peeked inside to see if they are sleeved. The front beam has been upgrade to a NG-37 Isomat section - this is closer to what Malcolm originally specced (the previous beam was well under-sized). After some quick percentage size math, I'm surprised at the variance between plan and as-built specifications on the cross-beam sections. That's probably a commentary on what was available in NZ vs. what was easily available where this boat was built in the USA.

 

This T9 was built in the early 80s and registered/launched in '84. She was born on the Pacific Coast and then received a major refit in the early 2000s in Florida, before being trailer-ed north to Canada. She has more wear from the shed than the sea since then, I think...

 

Martin, I will be spending some time on your site... great info there! I researched hard into GBEs before buying this T9, and somehow missed yoru pages.

 

Thanks for the welcome!

 

Randii


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#5 randii

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Posted 29 November 2018 - 08:53 AM

I checked, and there is no sleeving inside my T9 crossbeams. I've googled a bit with respect to what's involved with that... since my beams are oval or egg sections, there's no perfect 'stock' section available to insert. Short of having a Naval Architecture spec it out, is there any sort of best practice that's been done for the existing GBE fleet? Seems like the beam would receive highest loads at the inner-most hull/beam interface/connection/clamp and taper either direction along the beam from there.

 

As noted above, I don't think this boat has been sailed very hard very often, so failures haven't shown up yet. I'll ask the previous owner about the 'under-spec' front beam and whether it failed or was just replaced.

 

I will web-search more on this... since the beams are extrusion-formed, coming up with a composite insert seems possible, though certainly not simple. Maybe use the existing beams as a female tool and bladder-form reinforcement inserts -- I wouldn't say the T9 beams are 'roomy' but they would seem to have SOME room. Then again, why not reinforce the OUTSIDE of the beams (access is certainly easier for reinforcement and creating tube clamps).

 

Randii

 

http://crew.org.nz/f...ken-bmain-beam/

"Hilton, If the main beam was done correctly it should have had a sleeve inside it which runs the length of the section inside the hull and out up to about 300+ outside (depending on how much the last guy who built it had spare). This reinforces the highly loaded part where the beam leaves the hull (and where the dolphin striker bolts on underneath). It might be that the sleeve is still intact which is why the main beam didn't join the dots and come completely apart. The sleeve is usually made from a section of the same material as the beam but with part of it cut out length wise so it can fit inside."
 

http://crew.org.nz/forum/index.php/topic/15012-gbe-fore-beam-replacement/

"on multis all those wracking loads are at the corners and the strength there needs to be at least double the mid-beam
so with alloy beams you can either use a simple section, that's far too strong-heavy in the middle or find a way to get double or triple the strength at the ends
..."

"...alloy beams that aren't telegraph poles in the middle are going to need to be about twice as strong at the ends somehow
sleeving being the obvious solution
"

"... cut these 1mtr sections of the old beam in half to use as half molds, wax the inside, and glass in a few mm of boat cloth 1 mtr long, half-cure with the tubes strapped shut and some blown up wine bags against dry? cloth? forcing the wet cloth to shape, then deflate and remove bags to lay 900mm carbon strips inside that, half-cure again with the bags, lay more 700mm carbon, half-cure 600mm etc
try and bake your final mold  on a the dash of a closed up car on a hot sunny day, (reaches about about 50C), all day
crack them open the next day to remove your glass insulated carbon sleeves, ready for sanding rough, latering in an epoxy, adhesive mix and slipping into new beam ends
not going to be quick or pretty but the end result won't be seen and can be as strong as you want it"

 

https://www.boatdesi...24.27493/page-2

"The alloy crossbeams being particularly problematic, as suitable stock tubes the right length are not available here and mast sections the right size would need to be sleeved at certain points because the wall thickness was too thin."


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#6 TimB

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Posted 29 November 2018 - 01:38 PM

Randii, the accepted method for making the sleeves is to buy the same section extrusion as the beam.

The alloy beams on most tenant cats were typical mast sections of the appropriate size. 

You cut the bolt rope groove out. This allows you to compress it slightly and slide it into the beam. Usually riveted in place. some glue them as well.  Also you need to round off the ends so they do not form a hard point where they finish. .

 

Tb


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#7 randii

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Posted 01 December 2018 - 07:11 AM

Thanks, Tim... that seems eminently possible at launch or a few years back (the boat was first registered in '84).

With 34 years intervening and 4 different extrusions, I suspect finding matching extrusions will be challenging.

 

I'll search, but I may also need to prepare a Plan B, and at first glance, that looks like a composite insert.

 

Randii


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#8 MartinRF

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Posted 01 December 2018 - 09:10 AM

Unless the Isomat NG-37 is strong enough on its own.

 

Do you have the construction drawings or can someone else inform us on the dimensions of original front beam?

 

/Martin


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#9 MartinRF

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Posted 01 December 2018 - 09:28 AM

Epoxy only for laminating or also for sealing the wood surfaces?

 

Clear finish or painted?

 

Dagger boards and rudder blades are built how?

 

Aluminium cross beams? Sleeved?

 

How old?

 

Background to my questions:

 

* A complete seal -- inside and out -- is best. Epoxy is pretty good moisture barrier in my experience.

 

* Epoxy does not offer much protection from UV and it is vulnerabel itself. In my experience the wood below the epoxy degrades quicker than the epoxy and eventually mini-cracks deveop in the epoxy barrier when the wood-epoxy bond is gon. Hence painted on all exposed surface is recommended -- a recommendation I have not followed myself and the clear finished areas are the ones that have generated most maintenace work.

 

Clear finish on the inside is a good idea as it makes it possible to keep an eye on things.

 

* I don't think I have run the numbers for solid wood boards so I don't know if they are strong enough. It is very common to underestimate how big the loads on the boards can be. I know Ian Farrier lists solid wood as an alternative -- still with a substantial reinforcement running down each side.

 

* Tennant's aluminium cross beams are under-engineered in my experience. We had problems right away and I have come across a score of other owners with more or less severe problems to report.

 

* Age: General interest.

 

/Martin


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#10 ScottiE

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Posted 01 December 2018 - 03:33 PM

I'll see what I've got on mine and on the build plant that I have.
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After a decade or so of Euphoria . . . it's time to go Ballistic!
Anthony




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