This IMAC Breezer caught my eye some time ago when I saw it for the first time in the "wind surfer mast" post:
www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=48873

Looks like a sweet machine, except for the steering, which could be easily reconfigured to more robust design (minus ropes). Does anyone own one of these?

As a suggestion, I would recommend that you work on learning to build relly comfy seats. youcould teach yourself the basics of glassing on wood , then move on to building a plug ,mold and then a seat from a mold .
Fibreglass shops, books and websites all offer help, as would we, the first time you pull a simple seat from a mold you realize what a great and usefull skill youve learnt, that your kids have learnt , and the possibiities are endless.
I hadnt done any molding , and thought it really hard , then one day watched a kiwi fella pulling a nosecone for a gokart from a mold , whilst drinking a beer , all under his house, . when I asked how it was done he explained the basics,and introduced me to coremat. cheers for that kiwi307
Having built a good seat you then start fitting it to new yacht designs
your hooked now , so why stop

Bit of a bummer to build a nice class 5 and have to settle for a plank seat eh?!

I've molded composite parts for airplanes before, but nothing as big as a landyacht seat. I figured that's one of the next projects though. In some ways it seems easier to make such a big part because I won't have to deal with pressing fabric into tight corners.

Would be fun to build a big plastic vacuum forming machine. Build a seat for about $40 in 5 minutes once the mold is made.

If it was just the seat,the same construction method and styles as most of the plastic "kayaks" that infest our waters would do the job. a class 3 body would be another issue.
problem is that those plastics give quite a heavy product. A poly welder showed me some thin sheets he was using to build a dinghy with. he reckoned they were the lightest and thinnest stuff available . a 4'x8' sheet was 22kg . the plans he was using called for 6mm marine ply that weighed in at 8 kg per sheet .
when he finished the dinghy , I couldnt even drag it because of all the extras he'd added to stop the sheets of plastic warping.
the latest 'explorer' seat That we layed up in polyester resin , chopped strand and some coremat,for TEST PILOT 1, weighed in at 4kg, and he's no lightweight

This almost deserves a separate thread!
The reason I asked is that vacuum forming fascinates me, but I did not know of a thermo/vacuum plastic that would work. Kayaks etc are not made this way.
After many thousands of resin and glass objects of all sorts, I find it hard to get the enthusiasm to pick up a bucket of resin again, even for myself. As well having had so many of my products "flop moulded" ie you do all the development then some one comes and takes a mould cos they think they can do it cheaper than the product you are selling. (Hint look further up the page).
Vacuum moulding of resin still gets a bit sticky, but I am nearly ready to do some resin infusion just for the sake of it. The mould needs to be even more technical though, but you stay clean!

Paul, time to move on from the 1970's! There are better options than blotting paper, woops coremat.
I gave up on that where strength was a factor not long after the Kart nose moulds. Interesting that these are nearly always rotomould now. BUT the reason is that they do them from polyethylene is that they use them as "push the other guy" pods and 'glass ould not hack this for too long.
Coremat is great for adding thickness without too much weight, but contribute very little to actaul strength. I'm not sure if you remember but I used to add Qcell to all laminating resin to puff it out a bit. Intesting this gave a better result. But as usual, the way you know, and are happy with is always the right way!
Vacuuming is great IF THE MOULD WAS MADE FOR IT. It's very easy, saves a lot of the rolling, and gets very good structures. I can't really see why you would need to for a seat. You have achieved good weight, you have it done in good time (I like the comment about assistant!) so why change!

yes, now it's a blend and called micro spheres, I am not sure of the composition.
When Richard Honey, who is now the director of High Modulus Fabrics, and laminate engineer for all sorts of stuff, plnaes, windmill blades, Americas Cup boats etc was at uni doing his degree we made all the test panels for his research. Since seeing what happened I haven't used coremat again! But tthis was "extreme testing", dropped steel ball, spikes etc. It is great for increased panel stiffness though for sure. Star cracks are almost a given.
I am surprised it worked for your battens, every time I tried we got core sheer when the battens flexed, maybe the battens I tried were more flexi than yours.

I've used micro spheres. I think it's also called "fumed silica", or maybe that's slightly different composition. Sometimes I used powdered carbon as filler in carbon fabric layups.
Epoxy is my favorite laminating resin, but polyester is cheap and more available.

The layups I've done for airplanes are carbon/Kevlar/glass. Very light, very tough, very expensive when doing a large part and also overkill for a seat unless the seat is handling part of the frame stress.

I like the idea of doing a composite axle.

Some years ago my friend and I owned a microlight aircraft that had an undercarriage that would have been great for a landyacht, wheels and all
It too was composite aproximately 100mm across the top and two webs at 45 degrees of about 50mm in the centre and tapering toward the ends to about
half those figures Sort of upside down channel shape in cross section

Isn't the Blokart a composite axle? Certainly was the last time I looked! Pre-preg epoxy carbon glass!
Maybe not quite how most of us thought of it though. Many of the euro class 3's are using them (or were). The Charc (Georges Ameele) had one, the Glider from Seagull has them.
In a way Colin Palmers axles are, as they use(d) a cedar core for shape (not much strength in cedar) and then various composites over the outside and for the main web.
I never used them for 2 main reasons
1 Wood is cheap I used the normal Euro favorite of Ash.
2 Wood is easy to make more springy, the power planer works a treat!(That is very hard to do with glass or carbon, easy to stiffen, but hard to soften.)