Catamaran build/maintenance question...

[Alan.M]

Originally Posted by rob denney

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

Z pressing the panels took 2 1/2 (long) days for the entire kit. Sealing the whole lot could be done at that stage, and would possibly add another day to the process.





Taping the parts together is fast! You can easily fit two panels per day. Setting up the female frames took a morning, and I had the lower bilge panels fitted and taped in the afternoon.











Eight (8) days from starting the Z-pressing and you have a hull and half a bridgedeck ready to start fitting bulkheads.



Could be done faster too - I added a 100mm strip to the bottoms of my sheer panels to give more headroom. So I had to cut them to the profile of the bottom of the sheer panels, which meant a pair of 44 foot jigsaw cuts for each strip, and an extra tape.

By a boat like this I mean a similar size weight and design, but not neccessarily identical. I liked the Schionning wilderness 1230 too, but could see it was a more complex build, and it was also a more expensive kit. Very nice boat though, and I'd expect the extra cost would equate to higher resale value, but I did have a budget...

Bob's method of building right side up in female frames looked much easier than building upside-down working inside the hulls from 44 gallon drums too...

I looked into KSS, but it seemed very labour intensive. Setting up a perfectly flat, airtight table 50 or so feet long seemed like it would have been more work than building my hulls. Remember I was working on a dirt floor - the shed was only to stand as long as it had the boat in it.

Also from the workshops it appeared that with 10 - 15 people working over a weekend, they'd still only get one hull side infused.

That's 20 man days - I was about ready to turn the first hull by then!

[rob denney]

Originally Posted by Alan.M

Z pressing the panels took 2 1/2 (long) days for the entire kit. Sealing the whole lot could be done at that stage, and would possibly add another day to the process.


Taping the parts together is fast! You can easily fit two panels per day. Setting up the female frames took a morning, and I had the lower bilge panels fitted and taped in the afternoon.

Could be done faster too - I added a 100mm strip to the bottoms of my sheer panels to give more headroom. So I had to cut them to the profile of the bottom of the sheer panels, which meant a pair of 44 foot jigsaw cuts for each strip, and an extra tape.

By a boat like this I mean a similar size weight and design, but not neccessarily identical. I liked the Schionning wilderness 1230 too, but could see it was a more complex build, and it was also a more expensive kit. Very nice boat though, and I'd expect the extra cost would equate to higher resale value, but I did have a budget...

Bob's method of building right side up in female frames looked much easier than building upside-down working inside the hulls from 44 gallon drums too...

I looked into KSS, but it seemed very labour intensive. Setting up a perfectly flat, airtight table 50 or so feet long seemed like it would have been more work than building my hulls. Remember I was working on a dirt floor - the shed was only to stand as long as it had the boat in it.

Also from the workshops it appeared that with 10 - 15 people working over a weekend, they'd still only get one hull side infused.

That's 20 man days - I was about ready to turn the first hull by then!

Looks good.

Couple of things about flat panel building.

1) 15 volunteers is not the same as 15 workers. By the time you have explained everything, answered all the questions, sorted out the cock ups and fed and chatted with everyone there is little if any time saved.

2) The table takes longer to build than Z pressing all your panels, but can be used for almost every part of the boat, including the furniture, rudders, beams, mast and boom. The parts can be undercoated on the table, so there is none of the exterior filling and fairing that you had to do. Building a table on rough ground is pretty easy with star pickets and 6m lengths of alloy or steel tube.

3) Panels you make yourself will be cheaper than if someone else makes them.

4) Rebates for joins can be included in the laminate, which eliminates any full panel fairing, and with a bit of forethought can also eliminate almost all secondary laminating, including bulkheads.

5) You can vary the laminate in the infusion, which can save a lot of effort. Not sure if you added extra timber and glass to the bottom of your hull like Scrumble did, but this adds an hour to the infusion set up, compared to days to do it by hand.

6) You only turn the hulls once.

Using flat panels may have saved you some time and money to the built shell stage, but this would be be a pretty small part of the overall 6,000 hour/$180,000 build time/cost. Designers still have a very long way to go to make building a boat quicker and more affordable.

Are you heading north or south? If you are ever on the Gold Coast, please drop me a line so I can admire your handiwork in person.

rob

[Alan.M]

I know turning hulls seems like a really big deal to a lot of people. It isn't. You invite a few friends over - 8 is PLENTY - and have a barbecue. Turning a hull takes 1/2 hour. They are strong enough that you can just shove them around, and light enough to be easy to drag even on a dirt floor.

Also, even though the hulls are turned twice using Bob's build method, it really only adds on additional hull turning "event". You turn each hull once, then finally both at the same time. The advantage of being able to work "downhand" on both the inside and outside of the hulls far outweighs the one extra barbecue IMO.

It's never a problem getting volunteers, usually there are plenty of people interested in what you're doing.

You can save money by making your own panels, as long as nothing goes wrong. Infusing a panel over 40 feet long does give a bit of scope for air leaks though. And if you ruin a panel that big, it could eat a lot into the money saved. And you do have the added expense of the vacuum pump, all the resin traps, and all the consumables that go with infusion.

Anyway. using Duflex worked for me. I'm happy with and very confident in the boat, it performs brilliantly, often sailing to within a knot of windspeed, fully loaded for liveaboard cruising. I know the material to be tough and durable, from my own as well as other's experiences.

By building my own, I have a boat I couldn't have afforded to buy, let alone go cruising on.