Catamaran build/maintenance question...

Anyone else do pre made foam CNC stuff Rob. I like foam, just made my cabin out of out and a lot of the larger folder but no one makes CNC precuts in it like ATL do.

Maybe there is a market there for a bloke with a long table and a router. Really cheap version a bloke with a data projector and a computer. How is this Rob. Make a long table - make your foam panels on it. Then you get you cut outs from the computer on a data projector which also has a 200mm by 200mm (say) grid drawn on it. The grid lines up with the grid behind the cutouts and then you trace the cutouts. Do the job with a jigsaw. Or make your own router table. Or get the cutouts printed off by a printing shop. Have some grids to make sure the printout is scale and then use that. Much cheaper. Getting warmer - use the cutters used to cut acrylic names. Then peel off the stickers and place on the material you want to cut.

Cheers

Phil

 

Cool ideas, but there are already companies doing this at very reasonable prices and some of them (Pacific Multihulls in Coffs have a 12m table and router, as does someone on the Gold Coast and the guys who designed Spitfire in Perth, Wayne Hill in Brisbane), can make the panels as well. Or make them yourself and take them to a local cnc cutter.
There are plenty of cnc cutters around the place, I just had some frames cut out on a local 3m x 2m table which I found on Google.

Long panels can usually be laid out on the table as they are not complex shapes. They are much better than joined panels as the (very elegant) Z join is only 80% of the strength of the panel, which is probably plenty strong enough, but does imply that the rest of the panel is over built. There is also scope for much more variation in the laminate (particularly lengthwise unis) with long panels.

rob

rob

 

A boat bilge has fresh water in it?

Anyway, duflex does not require huge amounts of bog to fill the weave. I filled the weave on my sheer panels using a runny glue mix and for a 44' by around 5 ' panel, you would use less than 500ml of epoxy. You just squeegee it on as thinly as you can.

Bob Norson had some issues with the duflex he recieved, some were due to poor quality control, (possibly because he pressured ATL to deliver his kit before christmas when they had previously said they couldn't.) some were due to his build method. I actually helped him start his kit, and advised him to use a different method, but he was determined to do it his way.

ATL, in consultation with Bob Oram, offered him materials and labour to completely rectify the problems. Bob (Norson) wanted the entire kit replaced, so he wasn't satisfied.

Since then he has been running an anti - ATL campaign....

 

When you do a simple "destruction test", a properly done Z join is at least as strong as the rest of the panel. I'd say ATL rates them at 80% to allow for less well done joins.

 

Probably not, apart from rain (through hatches, windows or leaky deck fittings), condensation and spillages.

Did you check it for watertightness afterwards? If the surface area of the entire boat was say, 2,500 sq, that would be 11 kgs of epoxy and a days(?) work just to fill the weave, plus more for the tapes. My point is that if it was shiny, there would be no need for filling. Nor for fairing and painting, if the design used full length panels.

Thanks for the history. Have you done any of the tests on the absorption of water into Duflex panels that Norsrom shows on his web page? Were those on faulty Duflex?

Can't see why they would. None of their other materials properties data allows for operator error. Maybe they use complex (4 point bending, fatigue, tension/compression etc) rather than "simple" criteria. Regardless, the work of joining Z panels, and adding extra laminate makes them far more labour intensive than full length flat panels.

Rob

 

I wonder how much longer the flat panel balsa boat building fad will last.
Surely its almost run its course?

 

Ting Ting, let the balsa bashing begin

 

What would be the point of running those tests, when you simply don't USE Duflex unfinished?

That would be like testing an unlaminated foam core for it's strutural properties. Pointless, because you use it laminated. Or testing how long unpainted steel will last in a marine environment. You don't use it like that, so what's the point of testing it like that?

Full length panels are good too, but you have the shipping and handling difficulties that go with them. And you still have to fair where they are taped together.

 

Until the facts about creating a fair & gloss surface on the "kits" are disclosed by their builders & marketers, of course those biceps developed will help in hauling on sheets once sailing.
Regards from Jeff.

 

It isn't fun, but it's really not that hard. Just a matter of putting in the hours. More productive than sitting in front of a TV.




























I think it's good to be able to do something worthwhile in your own backyard.

 

Same reason Phil's mate put a piece of untreated Duflex in a bucket of water for 5 years. If you are going to religously skim and paint every piece of Duflex on your boat (inside and out), epoxy every screw, bolt and fittings hole and promptly patch any damaged bits, then there is no need to test it in it's bare state. For people with this approach (less than 5% of the boating population, in my experience), Duflex is a suitable, though expensive material. I would advise the other 95% to do some relevant tests before proceeding. I'd also advise them to carefully read all the "balsa bashing" posts, and treat with scepticism those from companies and individuals with a vested interest in promoting it.

I don't know much about Norsrom's tests, was just curious as to whether they were on faulty panels, and whether you had done any similar ones.

Full length panels do not need any taping, if the lengthwise joins are included in the panels, which is pretty easy with infused panels. Transporting flat panels is a small price to pay for not having to join the panels, fair, sand and paint most of the interior and exterior of the boat.

Is the boat in the pictures yours? Congratulations if so. Do you have any record of how long you spent sealing, taping, sanding and painting and how much you spent on the materials required for this?

Bruce, The fad will end when the people with the budgets and profile to promote it come up with a better way of making money. Cheaper, quicker techniques that use less material, or simpler building will not enter into the equation.

rob (who sold balsa for ATL when Durakore was first introduced,and imported Probalsa to make panels back in the 80's)

 

So we shouldn't be sceptical of any posts from people with a vested interest in denigrating balsa, right?

My boat took around 6000 hours to build, and materials were under $180,000 Au, that's launched, rigged and sailing, including electronics, fridge and freezer, etc etc.

I looked for a quicker and cheaper way of building a boat like this, but couldn't find one. There are certainly cheaper ways, but they take longer, and quicker ways are much more expensive.

 

You should be sceptical of them as well, but as far as I can see, no one on this thread (or even this forum, asfaik) has such an interest. Balsa is cheaper than foam, I would certainly use it if it was better for the job than foam.

Well done, has anyone any idea how this compares with a cedar strip or KSS boat of similar quality? Unfortunately, it doesn't answer the question I asked, which was about the joining, sealing, taping, fairing and painting time and costs. If you (understandably) didn't keep records, would you estimate that it took 50%, 25%, 10%, ?? of the total time and cost?

Interesting. By "a boat like this", do you mean an Oram design, or did you compare with other designs of similar length, beam, displacement etc? Do you have any actual numbers to support your result, or was it more of a gut feeling sort of thing?

I am not trying to give you a hard time, or denigrate your excellent work. Just trying to see why you made the choices you did.

rob

 

composite cleats?

Alan, How are the cleats holding up? Looks like an interesting solution. Are they epoxy glass? Does the paint wear off very fast (uv protection ?). Are you happy with their design and is there any aspect you would change? Interested.

Regards.

 

The cleats are holding up fine. Admittedly the boat doesn't spend much time in marinas these days... well pretty much no time in fact..... but for the first six months we were in a marina most of the time, while we were getting the house packed, cars sold etc, and they held up perfectly. Paint is fine on them, and I had thought it might wear off fairly fast in places. (One has some paint a little cut up from fishing line and a yellowfin tuna)

They are made from glass tube and glass rod from excel composites.

If I was doing it again I would angle them outward a bit more, to prevent mooring lines from rubbing on the hulls. That's about all I'd change.