Rotomolded Future

Is there a market in the USA for a rotomolded boat with a little more kick than the Getaway? Getaway is rated slightly faster than a H14 (as is the Dart 16). Something in the H16 range of speed. Since I'm wishing here, 14 to 17 foot, obviously boardless with a square top, high aspect ratio main, self tacking jib, optional double trapeze, optional spinnaker (G-Cat-esque).

Does this defeat the purpose of the rotomolded cat, or not, making it too hard for a novice to handle? Does the increased speed make it, comparitively speaking, a "dangerous" boat? Can enough bouyancy be built in to the bows to avoid pitchpole and keep the speed?

What US builder would potentially step up? NACRA? Vectorworks?

"Selling like hotcakes" <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />

Mybe a call to Tupperware is possible! If its not fiberglass its craaap! <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Is it Bob? Or is it progress? Old fiberglass boats are prone to delamination and generally don't look to whippy unless well taken care of. Sure, they can be fixed up with time and effort. Is that what we shall expect from an entry level cat sailor we're trying to woo into racing?

The Getaway looks...like another sailboat, a recreational boat. Why not a specifically designed sporty, entry level, potential racer that is quote indestructable. With new rigging, lines, sails they could feed a novice fleet forever, And feed the high performance fiberglass market.

You all remember when the Wave came out? The hard core racers thought it was a joke, but soon Rick brought a bunch of them down to his place for the "Wave Nationals" and voila, a new racing class was born. That's all it takes. It doesn't have to be a state of the art design, just get a bunch of them together and race. I would think a larger, two man or two woman or two kid, double trap 16 foot Wave with a self tacking jib, no boards, etc, would work as both a recreational boat and a racer. Like the Dart 16. You could even put the Hobie Bob on the mast. I would think the Motels would love it and could even sponsor regattas. I think the trapeze is necessary to get racers to buy into it, maybe offer a spin. kit as well.

How much is that new French cat, the 16' "Youth Worlds" boat going to cost when Performance starts selling them? Anyone know?

Isnt the Getaway a 16 footer? I would love to get my hands on a storm damaged getaway. I would double trap it, spinaker kit it and square top her. I would also put some wings on.

I think it would be a bas butt weakend warrior.

Just my two cents here. Getaways are total pigs, but I love them nonetheless. This is why: I don't own a boat. However, thanks in part to the popularity of rotomolded boats I can go to pretty much any beach and rent a cat. I think that's why they're selling like hotcakes: rental. Fiberglass boats are expensive and a pain in the butt to take care of. You can beat the crap out of a roto and leave some 16-year-old to take care of it, and it will last for at least 5 years. So, I don't think people are buying these things for themselves, I think they are buying them to rent to me when I visit Miami. I have what passes for a state-of-the-art rotomolded ocean kayak, and believe me, rotomolding has a long way to go before fiberglass becomes redundant.

The Dart hulls and boat overall "look" much sportier

There are pros and some substantial cons to rotomolded construction that you may not have considered. Yes, you can throw a rock at it or play bumper boats and not worry too much - but when you have holed it, you have a big problem. When your keel wears after the 100th time you slide it up the beach, you have an issue. The problem is that repairs of this nature on poly boats are very difficult if not impossible. You're not going to fiberglass it together and the "poly-welding" that used to be possible on them is not anymore. The the new cross linked polyethylene materials they are using to build these boats today are superbly tough but do not lend themselves to heat welding or other means of repair once the plastic is solidified. So yes, they are more durable but they are less repairable. Poly constructed boats are great for businesses that intend to depreciate and eventually trash the asset after several years. I wouldn't recommend it to a sailor that intended to use it at a high frequency for a lengthy period.

The tooling for producing a rotomolded object can more expensive as well but pays for itself through high iterations of production - so not suited for small runs.

By contrast, if you wear out the keel on a fiberglass boat, it's ready to go again after few hours in the garage.

The Wave class is a terrific racing class with very tight and very even competition. I think the Wave fills a very neat niche in the industry. Personally, I've had some of my most fun moments on one and would certainly have one in my backyard if I thought I had the time to sail it. Fair, even, and exciting racing can certainly be had on any rotomolded sail boat - speed is relative. I just don't think it's going to be the wave of the future (pun not intended).

I love mold.

I agree with Jake except for one area, repair. The cross linked plastics can be repaired, it just takes different tools. I have two, an auto body brazing tool and an industrial(high temp) hot glue gun. Both effectivly braze the plastic.

There are several other ways to repair this type of plastic(involving chemical reactions) but it's DIY, there are no kits available.

Found this regarding windsurfer repair (old BIC? notice the ref. to 1981 price), however it's confusing, not sure whether he's referencing cross link repair or using cross link to repair linear?

HOT AIR WELDING/POLYETHYLENE

We use the hot air welding gun manufactured by Leister Co. and distributed in the United States by the Robert R. White Co. The gun costs $385.00(1981 price). Special tips are required; these cost approximately $80.00 each. The most often used tip is ______ . This tip uses 3/16" extruded high density polyethylene. Also needed are scrapers for cleaning the polyethylene.

The cross-linked polyethylene that we use is known as a thermo-set plastic. This means that once the plastic is heated and melted, it cannot be melted without burning it. You need to use a material that is the same as the skin. ( Therefore, the kind of weld a hot air gun produces is not a true fusion of the plastic (as in metal welding, brazing or aluminum helearcing).

Experience bond and controlling the three variables are needed to produce a successful bond. Three variables are:

1. Cleaning both the polyethylene board and rod with a scraping tool.

2. Controlling the temperature of the tip of the gun at 3OO°C.

3. Drawing the gun across the weld at a steady controlled rate.

DON'TS

1. Do not try and melt the extrusion into the board.

2. Do not hold the gun for too long in one spot. It may bubble and delaminate the hull.

3. Allow the weld to cool completely before testing the repair.

The repair can be finished by shaving the weld flush with the hull with a sure form or sanding.

The hot air welder can be used to repair daggerboard wells, mast-steps, skeg boxes, and replace large hull sections that have been damaged. When replacing hull sections, mast-steps, and daggerboard wells, it is best to cut out the sections with 2-3" deep of foam attached. Bond this to the hull with the epoxy and then seal the perimeter with the hot air welder

You are not going to hot air weld crossliked PE. The plastic molecules have chemically bonded to each other and a hot air gun will not break these bonds, allow more material to be introduced, and reform the bonds. Older PE boats did not have the plastic crosslinked. This is why you can repair them by heat welding.

As mentioned before, crosslinking is a double edged sword... They are very tough and can take enormous amounts of abuse, but once you finally break or wear out the plastic, it's pretty much over.

The crossliking is also why not much sticks to the hulls.

How long does it take to wear down the plastic?

gonna use beach wheels? just because that's the easiest form of transportation, a helluva long time.

I know nothing about repairing Polyethylene. I do have a repair kit supplied by Laser for the Dart 16. 2 methods of repair are mentioned. One is Rod Welding with a Leister gun as described above by John.
The other is Powder Welding. For this you need a hot plate and frying pan, a heat gun and a putty knife. And of course the powder which is supplied in this kit.
This is heated at 150 C for about 10 mins. The area to be repaired is cleaned and sanded - broken bits cut away etc. The area is heated, the putty knife is heated and the melted plastic is quickly spread onto the area. When cooled smooth with chisel or block plane. Finish by sanding and heat polishing the area. To heat polish: sweep the gun back and forth across the area until it glosses over.
That's what Laser say anyway <img src="http://www.catsailor.com/forums/images/graemlins/smirk.gif" alt="" />

I'm getting sick from the dizziness <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" />

"Yes, you can!" "NO, you can't!"

Check out the lead boat sailing uni...Dermot?
Dart 16's and large, orange floating object

OK, I guess the Laser material is NOT cross linked.

It is Techrothene 109, from the Laser Pico brochure;

Techrothene 109 is a linear high density UV stabilised compound moulded into a stress free homogeneous sandwich with an inner closed cell structure.

Exceptionaly Strong
Incorporates built-in buoyancy
Superbly Stiff
Highly resistant to scratching and impact damage - easy to repair

So why doesn't Hobie use it?

Link did not work <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />
Laser also call their material Techrothene 121 <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />

http://f7.yahoofs.com/users/45435740z678f1583/ee50re2/__sr_/32d5re2.jpg?phweQSFBNT1Tq5kr

http://pg.photos.yahoo.com/ph/catsirl/detail?.dir=ee50re2&.dnm=443are2.jpg&.src=ph
Same Event - This years Nationals. This one is "Dermot" I won that event <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />
Total 27 cats: 9 Dart 16s, 2 Dart 18s, 1 FX-one. The rest were Spitfires, Tigers and Hurricane 5.9s.

Great slide show Dermot! Nice job on the first place too, looks like you had plenty of wind.

Actually, Hobie did originally use linear polyethylene but I believe they went to the cross linked poly about the same time they started making the hulls thicker (or double walled I think). I believe they made the change to increase the durability of the boat (it also made it heavier).

There are resin systems available now that will repair all the poly products. They tend to be very expensive and many were originally developed for the automobile industry particularly for repairing "thermal" bumpers etc, also as glues for bonding metal panels to metal instead of welding as well as metal to any/all types of "plastic" and of course plastics to other, different plastics.

Thanks Tim.
I know that I am "off topic", but there are some video clips taken the evening before the event on www.catamaran.ie No. 1 is a good one of Amy Jayne, driving the Spitfire downwind from the wire.

I just watched it, very nice, where was she sailing?

I wonder if it would make sense to attach a solid, sacraficial strip or sole of plastic to the keels so that they could be replaced when they start wearing down. Some of the big cats do that.

Old Towne Canoe sells a kevlar stip to glue onto the bottom of canoes for that reason, you could probably do the same with any cat, I don't know if it would "stick" to rotomolded plastic though. Maybe Hobie already sells one for their kyaks?

How 'bout screws or rivets?

If its not carbon its crap.

The Dart 16 weighs much less too.

Its in between the Wave and the Getaway in terms of performance. I was disappointed when I rented the Getaway, way too heavy.

This coming from a man with a carbon fiber A cat. I have to wonder why you even mentioned you were on a roto-boat when you think they stink so much?

That is like a jet fighter trying a 2-seater Cessna and commenting on it's performance. What can you know about low performance catamarans? You sitting there all high and mighty on your speed demon, looking back at the rest of the World.

<img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />Dan

The Dart 16 is not as slow as some people think, sailed singlehanded, it is rated faster than the Dart 18 and the Hobie 16. It points much higher than either of them.
In a force 5, I have seen equal ability crews racing head to head, Dart 16 and 18, both two up. The 16 reached the top mark first because of its pointing ability. The course was triangular - a beat and 2 reaches. The 18 only caught up at the bottom mark and the 16 was ahead again by the top mark.

Tim, The video clips were taken in September on the Friday evening of our Nationals at Lough Derg on the river Shannon.

AHA! So there is capability of "more kick" than the Getaway in a roto boat. Dart 16 faster than the Hobie 16? Oops, I guess Hobie won't be building a speedy roto model (oh yeah, in 10 years...maybe). So there's NOT a market in the continental US for a boat such as the Dart 16?

Dermot,

With all due respect, but your following statement is not true.



Compare the SCHRS (ISAF) ratings : source www.schrs.com (lower number means faster)

Hobie 16 = 1.16
Dart 18 = 1.18
Dart 18 cat boat (1-up only mainsail) = 1.19

Dart 16 = 1.28
Dart 16 cat boat (1-up only mainsail) = 1.26
Dart 16 spi = 1.25

Wouter

Unfortunatly there is no way to repair a storm damaged getaway. Remember they are made of plastic... <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

The reason these boats sell well is not because they are made of plastic, it is because they are simple and robust. The reason they are made from plastic is that it is a cheap process, when the boats can be sold in large enough numbers. They can be sold at a similar price to a GRP boat and can therefore be sold at a higher profit. With the big companies profit is important.

The majority of sailors don’t care about performance. And certainly performance doesn’t sell in large numbers. You could make a rotomoulded boat of equal performance to a GRP boat but the complexity required would not make it popular and it wouldn’t sell in large enough quantities to make it financially viable.

As for reparability, they can be repaired, its not as easy as GRP, but you don’t have to do it that often. In fact has anyone ever seen a damaged rotomoulded boat?

So to answer the original question



I think the answer is probably no.

Gareth

Wouter, Wth All due respect - you missed the Dart 16 Sprint = 1.13. Now this does include a spinnaker, but if you take that out, you get approx. 1.15. Lower number than a Hobie 16.
http://www.schrs.com/cgi-bin/doc/schrsratings.pdf

Sorry Dermot,

But why are you comparing a Laser 16 sailed singlehanded with mainsail, jib and spi with a doublehanded dart 18 or a singlehanded dart 18 with just the mainsail ?

Wouldn't it be a better measure to compare this Dart 16 rating with a Dart 18 or Hobie 16 that was being sailed in a similar way ? As in singlehanded with jib and spi as well.

Only then will we get a proper feel for how the Laser 16 can be expected to perform.

Wouter

Wouter, All I said was: "The Dart 16 is not as slow as some people think, sailed singlehanded, it is rated faster than the Dart 18 and the Hobie 16."
I was not including the spinnaker. The SCHRS for the Dart 16 singlehanded with main and Jib was always 1.15.
Basically all I am saying is that even though it is a rotomoulded cat, it can be quite fast.
Why are you calling the Dart 16 a "Laser Cat" That was just the name Laser marketed it under in the US.

Ohh, it is definately the best rotomoulded cat design that I'm aware of. Many times better then the others.




I don't know. No particular reason. I think in the beginning of this thread I used the name Dart 16 and only after Bills post started calling it laser cat.



Still the SCHRS handicap uses 135 kg for the complete ready to sail boat; With each hull quoted at 48 kg by Laser themself ( http://www.lasersailing.com/disp/uk/dart-16/vital-statistics?i= ) I find that suspect.

On the website http://www.dart16.com/ they even claim that the alu mast weights only 10 kg !

Texel measurement says the boat ready to sail is 150 kg.

Now I don't know what is right (although I think 150 kg is believable) but if 150 kg is used then Schrs handicap singlehanded no spi comes out at 1.18.

That still makes it the fasterst rotomoulded boat outthere. And it is heaps better looking then the rest.

Wouter

So with the Getaway tipping the scales at 390 pounds (177 kg) and only slightly slower than the Dart 16, I suppose Hobie USA has done as best that could be expected, performance wise. They certainly have found a niche with a stable craft with a high payload capacity. In regards to "the majority of sailors don't care about performance", seems like a catamaran has to be one of the logical choice if you do care about it, so I'm not ready to sluff it off as not applicable.

Is the material and moulding process such that durability suffers with lighter hulls? Could not lighter and more refined shaped hulls in addition to a larger rig, without the complexities of a high performance mast and daggers, produce a boat capable of a 10% speed increase?

One of the problems in making rotomolded hulls is that the material does not have stiffness in flat panels. Due to the manufacturing process, putting in stiffening members (frames and stringers) is very hard, and would add more weight. So you need to design in support in the hull shape itself, or compensate with thicker hulls. So there will be limits to what you can achieve with this construction technique.

I think you have to bear in mind that rotomoulded dinghies are improving rapidly - you just need to look at the Dart, Laser or RS ranges and see how they've progressed from small, singlehanders like the Pico and Topaz to "full sized" boats like the Xenon, Omega and Vago in a relatively short time. The Dart 16 has been around a while now and it certainly can't be state of the rotomoulder's art anymore. I'm sure I read that Topper are launching a range of rotomoulded cats next year (I'd guess at the London Boat Show in January). It'll be interesting to see how they go.

Laser claim that the new Dart 16X has hulls that are stronger and stiffer and almost 15% lighter than the original boat. So, presumably the technology has improved.
The new Toppers are also Yves Loday designs and should be interesting.