I know that I am getting fatter as I get older, and so is my crew, so the F20 class is definitely where we are headed!

F20 or F20S(uper)/F20HT? I assume you mean the latter, which is the same thing for me.

well you are more then welcome to help out I'm sure... <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Yes, but I don't know about F20HT. Would that be a uni-rig? I prefer a jib for distance, as some portion of a distance race invariably ends up a beam reach.

I am not sure, but I think a sloop rig works better on that point of sail?

So for me -
10ft beam, 20 ft. length
boat weight under 350 lbs
sloop rig with spin
Wing mast shape (maybe)
double trap
daggarboards you can raise/lower from opposite hull (foils, maybe)
mast controls (outhaul, downhaul, rotator) led to skipper position
Trampoline easily removed from hulls (to facilitate breakdown for travel)

350lbs or 159Kg is a sensible min weight. Much like the B-class used to be.
I have suggested earlier that a new 20 foot formula class should be based on the old B-class design envelope with some additions. E.g. upwind sailarea 25square meters and 45-50 downwind, double trapze and the an affordable min weight attainable for home builders. The rest like daggerboards, mast controls, mast crossection etc. to be determined by the builders. No foiling, except alternatively for T/L foils which dont exceed the platform max width.

To make sure the boats are versatile, I would definately require them to be rightable by crew in all conditions. Further, all championships should include a distance race.

But we have discussed this a lot earlier. What we need is the magical mix of interested sailors with the will to get some boats in the water.

By the way.. Are you just day dreaming, or are you ready to commit yourself on a project? Would you be willing to modify a boat or even build it yourself, or will you not get involved unless you can buy a ready boat? Very few beasts like this around by now, except the Tornado and perhaps some ARC models?

Dont mean to be blunt, but it would be refreshing to hear that someone was ready to go further with a F20(S/HT) <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

make the weight 300

In an article or add a while ago in Multi hulls International I saw a cat called an"Exocet" low profile with tunnel like shaped hulls claims of 15knots in 10knots of air upwind <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />,20ft,lightwieght, roto-molded and looked futuristic anybody know whats up ? I believe also it was from France...

Unfortunately, I have neither time, ability, nor the space to design or build my own sailing craft. The closest I ever get to that sort of thing is gelcoat repair.

Another N20 is on my agenda for December 2007 unless there is something out there as user-friendly and significantly better in that price range

I guess I would be willing to modify an N20 to 10' beam if it wouldn't damage anything. How would that change the forces and vectors? I'm thinking specifically about the shrouds and bridle arrangements.

Rolf

I think that if you look at the three big boat classes which have emerged in the EU in the last 3 years, (VX 40, the Decision 35 and the Ventillo M2 (28 feet(, you will find that the common thread is that each class is designed to compete in a major series. Moreover, these are SMOD classes which allows the factory to get behind the effort and promote it as part of their buisness plan.

A Formula 20 class will only get going when you have a race....eg the Worrel 1000 or Tybee 500 which promotes the class, or a high profile buoys series that draws the interest of the pros or serious sailors.

The niche for a formula 20 is for sailing teams 360 and up! While I fit that boat.... I am not sure how many teams are out there for this niche.

(The Tornado and F18's are sailed by the same sized teams... IMO... essentially a Pro class and an amatuer class in the F18s with some cross over)

I dont know much about the Decision35 or the Ventilo M2. I think I read somewhere that the Decision35 was ment to stop an arms amongst pretty well off racers on the lakes in Switzerland? The Alinghi cat was one of the most extreme examples of this?
The VX40s are a creation of Mitch and Herbie, trought their TornadoSport company, and it is a commercial venture. I dont know how much Marstrøm contribute in the effort? But your point is well taken, you need manufacturers and builders to succeed. Not only in supplying the boats, but supporting the class.

I agree that you need something like a Worrel1000 or other high profile event, but what should come first, the boat or the event? Chicken and egg paradox in my opinion. The F-16 class grew without a major event trough their versatility, usability, affordability and performance. I am more inclined to that model for starting a class and growing it step by step instead of betting everything on a high profile event (which might fail).

360lbs and up sounds good. Obesity is becoming a problem in the western world <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" /> I am pretty sure the average weight will increase in the future. If you are lighter, get some sails to fit you within the design envelope. Light teams can also be fast until the wind really pipes up, but how often do we sail in those conditions (as Phill pointed out). However I think there are more 'heavyweights' struggling to keep the match weight in other classes in the western world than the other way round. Except for the Star class..


I can't speak for others, but there seems to be interest. I also firmly believe we need some new boats on the water before this comes any further. The right mix of people is also needed, but I dont see them here right now.

Ah... which of the two models to pursue. The F16 model or the high profile SMOD model.

I would note... that at the time, the F18 class was growing. The F20 class was fracturing apart and the 16' footers were an after thought. Wouter and the others saw the niche and developed the boats by home builds, modifying existing boats and enrolling builders over time. Its still not a big class... but it certainly has potential for lot of people who single hand..., are of small stature, or want to start sailing with a kid in a high performance boat.

Meanwhile, the F18HT class took advantage of the exchange rate and NO 18 foot racing class in the USA and tried to build a circuit of races. The Worrel being the most prominent. Most of the races survive.... the class did not.

IMO, the market niche of sailors at 360 and up is squeezed from two directions. the heavy weight owner can find a flyweight but strong crew and go compete on the F18's. If that is not enough for them... the existing Nacra 20 provides just enough juice in this niche to stop all development of an HT boat from most buiders point of view.

IMO, In the USA, I would count on home builders and sailors interested in the custom M20 or the Eagle 20 flavors to modify or build boats that are trying to win the elapsed time records of the Miami to Key Largo Race, The Mug Race, The Statue of Liberty Race on the East coast,
Those race will prove the speed potential... If the boats sail well... they will also be perfect for windward leeward racing if you can get a group of similar performance boats to the line at one time.

In europe, Texel and Carnac come to mind as events that you would target with your HT 20 projects. I don't forsee a big buoys racing scene developing around the 20's. There is simply too many options with the F18's.

In the end... I think of the HT20's much like the keel boat sailing in the USA... They mostly race handicap on point to point or 1 big circle a day on the bay and once or twice a year they actualy do three days of windward leeward races (NOOD and Labor Day Race Weekend)

Mark,

I am isolated in the outskirts of Europe, on the western coast of Norway. There is not much I can do, but what I can do will be done. E.g. there _will_ be a new 20 footer here in a not too distant future, under an alu Tornado rig. I dont think running an event here will draw a crowd, even if it could be quite spectacular.
Check Google Earth,
64°51'48.93"N
11°14'13.59"E
to
62°28'47.72"N
6°12'20.56"E

Lots of nice scenery here, and predominantly northly mixed with western winds. Lots of places to stop, and all logistics could be done over the coastal express (http://www.hurtigruten.com/en/default.aspx). Start and finish can be extend as far north as you could possibly want, while Bergen would be the logistical endline as the coastal express ends there: 60°23'19.17"N, 5°11'54.77"E

I think you have a good point on what direction the growth can come in the US. I dont see it happening tough, as there are no boats buildt professionally and homebuilders are far between. But things are happening, so perhaps there will be a new breed available in some time.. Things are happening on the homebuilding front with new building techniques, so perhaps homebuilding also becomes "easier".

Amongst the races here in Europe, the Round Texel is the one to participate in, with the Dutch open race week during the week before. But building the class is all about fun, affordability and activity at the local level (you and I know a bit about that from the tornado class).

I dont like the name F20HT, as it is too close to the F18HT and you in the US have some sore memories. F20S(super) or F20HP (high performance perhaps)?


Thanks for your interest by the way! I am certain the Tornado would be highly competitive in an F20HPS(orwhatever). Could even replace the centerboards with some daggerboards and inserts for even better windward performance?

Comparison to keelboats is down right blasphemous <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" /> Certainly we could do better than that.

Anyway, until the right mix of people get together and things start happening, this is all hot air, but fun hot air. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Rolf et.al.,

I tried to run a search for references to books on how to build your own boat. I presume using the GRP (glass reinforced plywood, correct?) method?

Where would one start with this type of thing? I know it would most likely cost more to home-build a boat (in time and materials), and that's assuming there are design plans already out there....

How did you and other home-builders get started? I'm not an engineer, either....

There is the eXploder 20. Not new though.

http://www.exploder.info/eng/content/view/46/130/

The standard work on boatbuilding for us is "The Gougeon brothers on boat construction". It's a very good read if you are interested in boatbuilding, wood and epoxy.

One can also build a one-off foam/glass/carbon/kevlar. Look at Ian Farriers site for more info about this.

Then you have the Derek Kelsall system (KSS), which can be downsized to one-off beachcats.


I got starte by following plans and learning by my mistakes when (mis)interpreting the plans.

I've been reading on hull materials from some marine surveyor who is really upset about how poor the cored hull construction methods are.

The author touts that foam doesn't stick to the epoxy (no matter what method is used), they don't resist impact well, bad with heat/water/UV, etc.

The balsa cores are the only "marginal" cores in the author's opinion, and they absorb water & rot (which leads to failure, but not 'catastrophic' failure)

In addition, he points out, the labor costs are higher because of the skill needed for core bonding, infusion, etc.

For any high stress application, the surveyor points to solid core construction (which undoubtedly must be heavy)

Are cored hulls primarily employed for weight savings only? What other advantages do they offer?

Cored hulls are lighter, stiffer and often stronger than solid laminates (they also offer better insulation in colder climates). It is true that they might be more fragile than solid fiberglass if thrown up on a reef or similar, but that is not what you build boats for. It is considered kind of outside the design envelope <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />
I suspect the surveyor you have been reading about is yearning for past ages.. Look at the most extreme boats and how they are designed and you will find sandwich laminates. The same is true for mass produced boats and modern aircraft parts. In short, cored composites are here to stay and when done right they are both long lasting and better in all ways than solid fiberglass or traditional wooden boats (some of the woodies are quite amazing even by todays standards. Both traditional boats/spars and epoxy/wood construction). If you want some good PR for wood/epoxy, try to get your hands on the Gougeon book.

Good points. "Old" sailors have commented that today's boats suffer pressure dings much more easily then "old school" boats, and I presume this is due to the cored nature of the hulls.

Of course, "old school" boats are probably the reason most "old" sailors have back problems!

Is there a good reference on composite materials (other than the ISO manual) that could be used (such as kevlar) to add a bit more ding resistance but still keep the weight lighter than solid fiberglass hulls?

And have they improved the bonding between foam core and glass? The surveyor photographed several cases from well respected power boat builders where a particular product line (boat model/class) had issues with poor core/glass bonding, despite the use of various bonding agents.

I think the surveyor said that it's no use to add carbon to the e-glass unless you add enough carbon to assume the whole load (he was speaking in regard to chainplate anchoring). I think I follow his logic on that, as I presume if the glass separates, there won't be enough carbon fibre to carry the load, increasing likelihood of failure.

"Ding" resistance is a product of the core used and the laminate on top. A heavier core often results in less dings. But it's always weighted against weight of..

Delamination is an issue, but not often. You can go over the top and fill the foams surface with a thickened mix of epoxy before you add glass, but that's heavy. The same goes for infusion <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" /> Delamination is not a large problem today as far as I know. Technology must have improved since the early days, but I dont know the spesifics. Vacuum bagging is probably part of the solution.
Powerboats see far different loads than our beachcats, it's probably two different worlds engineering wise (I am no engineer, so I am guessing).

Carbon on top of E-glass is a waste unless you design it so the carbon is able to take all the load. Glass and carbon stretch at different lengths, so the carbon takes all loads until it snaps, then the E-glass can start taking the strain. It's like you hang a 100Kg weight from your roof in a bungee. The bungee stretches rather a lot, but if you add a steel chain and hang the weight on both the chain and the bungee the chain will take all the load unless you shorten the bungee (or almost at least, you can always do something funky with the setup, but you get the idea).


We are getting quite far away from the subject: New 20foot beachcat designs..