Un-flippable Proa

I took out everything that was personal, or not about boats and there was nothing left, so it looks like this part of the thread is over.

Looks like we agree to disagree about what makes a good proa.

I am disappointed you have such a poor impression of me. Maybe one day we will meet and I can correct this.

Re your "plans updates". Harryproas are continually being altered and improved. I do not revise every set of plans each time I try a new idea. If you send me an email, I will do what I can to correct anything you think is missing in the plans of whatever part you are building. If you want to build using the new flat panel method, I will supply you with new drawings.

rob

rob

 

"I took out everything that was personal, or not about boats and there was nothing left, so it looks like this part of the thread is over."

That is probably a reasonable outcome, though there were certainly some points about boats.

"I am disappointed you have such a poor impression of me."

Not in the least, you are a constant source of interesting ideas and bold builds. I just don't agree with everything you write.

 

Derek asked me to post this. I pretty much agree with his comments on materials and KSS as a building technique for rockered hulls, based on my attendance at a workshop we put on to find out what it is all about.

For unrockered hulls, such as a harryproa uses, we have modified/simplified the technique considerably to get quicker, lighter, easier to build hulls.

THE SKEPTICS.

Hi -----

Thanks for the opportunity to explain the KSS building technique and explain why it is the most efficient way to build a catamaran, with zero compromise of performance, using materials which have stood the test of time over forty five years and promise still sailing for another few decades – and all at least overall cost. Add that vacuum resin infusion does 95% of the onerous sticky smelly handling of resin at best quality and, I think you will agree, we have something to shout about. The builder even gains from having to empty his rubbish skip less often as there is very little wastage. Where else could you see a 40 ft. hull progress from bare table and basic materials to fully shaped hull, with gel coat topsides etc., in four days.

If we break KSS down into its number of basic steps it is simple to understand and equally simple to put into practice.

Topsides are complete, full scantling foam sandwich. The area is stiff enough to ensure a perfectly fair line but bends to the gentle curve of a cat hull without forcing. The round bilge below the topsides is the equivalent of using a strip style process of foam with one light skin. The strips are cut into the lower edge of the topside panel, ensuring those ends of the strips are perfectly in line. Each finger as we call them bends to the section curve required. As there is compound curvature required of the final shape, the cuts are dart cuts, taking out slightly more material than a single cut. We have a set distance over which to bend the finger and hence limited chance for the shape to divert from the planned shape. The width of the strips and the width of the dart cuts we can predict. The slimmer the hull the wider the fingers and the shorter the cuts. Fat hulls present no great difficulty. Nothing there too scary and all basically tasks we have used for 45 years.

How to control the full shape and how much control do we need? We could, if we saw the necessity, set up full length frames for the full shape with battens for the round bilge area then apply the panels. This would not be a particularly time consuming task and would remove this favorite source of criticism by the critics. However, the theory told us that we can achieve an excellent result more simply. Practice has produced two well tried and proven options, depending on the particular project. I have myself been responsible for shaping about 35 different hull designs over the past ten years. We would never accept some inferior standard as some competitors would like to suggest. It takes a great deal of practiced skill to achieve the quality and precision which KSS achieves through technique.

As to hull shape, there is no restriction on the shape of the water line or of the keel line, providing these are drawn fair. The entry can be as fine or a full as required. The transom can be wide or narrow or the hull can be double ended. The slim hulls are simplest but only by a minor factor. The prismatic coeficient is not determined by the method. What more can you ask for? I suggest that all of this is obvious to anyone who studies the process.

RESIN AND FOAM CHOICE.
If any owner is not persuaded by my experience, which is that all the boats I have been responsible for since 1965 are still sailing or have been lost for some other reason than age. There is nothing in the KSS technique which requires a particular resin type. For myself, I do not believe in fixing what is not broken, particularly when it involves a lot more cost and more hazard to health. We have never seen one single piece of evidence to suggest that any Kelsall would be one jot better today had we used epoxy throughout. We do specify a good paint system and that ensures the durability of the polyester or vinylester resin. The same quality paint system is needed to protect an epoxy laminate against UV deterioration. We have examples of foam which have been fully exposed to tides etc., since 1969. See www.kelsall.com.

Anyone considering building should look closely at all the options. Ideally attend one of our KSS workshops – I guarantee it will be time and money well spent and it is fun. Any questions from any source are always welcomed. Definitely not essential. Most come to the workshop to see for themselves whether it is as simple as it looks but have heard skeptics views. Professionals come for same reason.

By panels, I assume you mean the 8 x 4 type. 8x4 is a small part of the typical cat part. Those panels are very far from Done compared to the KSS panel off the table. Join, finish, edge treatment, scantlings and fiber orientation to suit best structure, capped openings etc., are all missing and when those parts are put together, ready for next stage, they will have taken more time and cost twice as much. There is a good chance they would be balsa also.

Now ask yourself one question, would a pioneer of using foam with an unmatched record of sucesses, 400 designs, who can claim to have been the prime mover in the use of the mold table and of resin infusion on the table, which are the in words with boat builders today, and who runs an active design company operating in dozens of different countries around the World be offering some inferior product?

KSS is the outcome of always being on the lookout for ways to improve over 45 years of using the same basic materials. No other system has been subject to any long term development. Of course, there are followers who have taken on parts of KSS but we still stay ahead.

Reminds me of a story. A very experienced KSS builder, who has managed several projects was talking to the owner of a well respected boat building business. “KSS – that is Kelsall Silly System”, but after a long pause, he asks –“does it work?”. Unfortunately this illustrates the attitude of many on all sides of the boating industry who stand in the way of progress, to the detriment of the industry as a whole.

Do tell us who you are and on what basis you have formed your views. This would help others to judge and to help us ensure that the correct information is available, perhaps with more detail needed.

Happy boating,

Derek.

 

Look I am all in favour of any opportunity for a commercial, but if we could return however briefly to what I actually said it breaks down as follows, lame humour removed:

- "I don't believe it is as designeable as panels

Basically what I was getting at here is that there is great, simple even free, software for a number of hull design systems. You decide what you need, make the appropriate entries, you get a raft of performance info, and design info, and the hull builds out exactly as you want it to. And presumably great designers have less garbage in garbage out, but the system is very capable. You design a spehrical object, you get a sphere, not just a somewhat fair approximation that works just as well in the real world, mostly. Wait till you launch it to sketch the waterline.

I also believe it isn't as accurate or controllable, though that isn't exactly what I had in mind when I wrote the above. Let's look though at what Derek says:

"As to hull shape, there is no restriction on the shape of the water line or of the keel line, providing these are drawn fair."

That is some minor restriction, are we including step hulls, or bilaterally asymmetric hulls? No biggie, but my side of the argument was at the margin anyway.

"The entry can be as fine or a full as required. The transom can be wide or narrow or the hull can be double ended. The slim hulls are simplest but only by a minor factor. The prismatic coeficient is not determined by the method. What more can you ask for? I suggest that all of this is obvious to anyone who studies the process."

Yeah it is obvious, and what is obvious is that these are wholesale effects. Derek is an outstanding master in his field though there may be a reason why his hulls are less noteworthy aesthetically than Newicks, (who knows he used CC and the master mold a lot). I like tortured ply, and in a similar way it has limits. But it's like the Stones said, "You can't always get what you want, but you get what you need. That is a good deal with a fast system, but it isn't as designable. So I don't doubt I am right, but I don't understand why this is such an apparent insult. Multi chines aren't optimal either. Wharram hulls have all kinds of problems in oversimplification and fairness. With HPs in particular wholesale effects are pretty reasonable. Multihulls have always been hull build by system obssessed. Master molds, cc, cm, tortured ply, KSS, etc... No perfect system.
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- "it seems to require EVEN FOR YOU, the presence of the international visitor"

There are two claims here. One is pre the international visitor, you were doing strip plank, after that resin infusion etc... If not as you say KSS. But this is essentially a guess, so if you deny it, that is good enough for me.

The second claim is that many people require that kind of help. That is a bit unfair, because I haven't even seen a set of plans (the average plans over the average period KSS has been around). But I do recognize the signs of the adoption period, as people get real excited about this system, then organize a potluck, and so forth. Nothing wrong with this, and perhaps Derek will say to all future builders "for goodness sake please stop calling, if you can't figure it out for yourselves you are too stupid to build KSS" but my observations to date remain.

- "And it uses bad resin, and cheap foam"

This was a cheap shot, and I gather it is pretty good stuff, these days Am I mistaken that it was poly and open cell at one point?. I don't think it is corecell and epoxy to which I am biased, and I thought a lot of others also, but hey, maybe the consensus is that it is better still. That said, what is the best boat building material? I am as entitled to my opinion as are you Rob, and you have been quite wide ranging in your tastes. So how important can it be, or I expect to see those strip boats off the brokerage site, ASAP.

- "and the people end up with infusion software, and a website, and a whole bunch of stuff whereas the guy with the stack of panels is done. . "

And again, this is my observation, people enamoured with this system are either propellerheads to start with, or they are driven to this complexity in response to the system (or my sample is too small, but it's my sample). Let's not forget, there is resin infusion hardware, and expensive courses around this stuff. Not something I made up. There isn't paint the glue on the 2x4 and clamp it to another 2x4 software. Just sayin. Obviously the software is intended for complex projects, but a lot of people seem to get right into it.

In the past, I have criticized the claims of fairness in KSS. Sure the stuff comes out smooth above the waterline... However, I don't know current designs, and maybe the cuts and darts under the waterline are all gone

Some of the original was written in jest. Some of it was personal opinion. I may have latched onto the wrong facts, but I didn't do it out of expectation of personal gain, or ill will. This is how the system hit me. I love to build stuff and I would probably be really stoked if there was a seminar near me some day. I'm in no doubt that the boats can be excellent, got some opinions though.