Polystyrene boats

[Guest]

Check the home page and tell me whether it will work.

[Guest]

Dental Floss?

[Guest]

Ive repaired sails and made fishing lures out of dental floss - it's quite strong. I was wondering about polystrene as a core.

[Guest]

Kevin Trotter made a polystyrene Cherub in the early 80s. Was too heavy. Probably ok for a canoe.

I think another option is to use the polystyrene as the mould, glass over it then remove the polystyrene and add wooden frames.

[Guest]

This thing looks like a disaster waiting to happen!

 

Systems Thunder is made predominately of foam and I think Poly too? Not 100% on how it's all laid up....But covered with plenty of eco friendly carbon in the right spots....

[Guest]

Poly cores are far from new. One of our 18fters was glass over a polystyrene core, I'm thinking early 80's. Was OK but went soft quick and changing gear around was a tad tricky at times. She lasted 2 seasons as a good boat but sailed for a couple more. Mind you it was, as many 18's were in those days, only build to last a season or 2.

 

It was the same hull the Minties people wanted us to sail into Orakei wharf at speed for one of their Minties moments adverts. All set to go and the plan got binned at the last moment due to the large possibility of filling Akl Harbour with masses of floating crap. Shame really as we lads were 200% fired up and looking to destroy a boat at 20 plus knots. Plan was kite up and high speed into it and we'd, the crew, bail at the very last second.

 

There was quite a few poly core boats being done at the time. One noticeable one was a big round the world racer, I think for the Whitbread, someone will remember. One of them loonie french dudes (maybe a pom??) got a giant block of foam and carved it into the shape of a 60fter then glassed it. From hazy memory she was the top or close to boat when she 1st went splash.

 

Works OK but has no strength of it's own, unlike cores today which have some, even if some have knot a lot, so if you don't lay the boat up with enough glass in the right spots they quickly go soft and once that happens she's pretty much a dead duck. But done well it is still an option and can produce a very lite boat.

 

You'd be hard pushed to get me to do a poly core these days. The alternatives are just so much better. Good for certain components though. Today many of the smaller fizz nasty builders get big blocks and CNC them into plugs for their molds.

[Guest]

Thanks KM - I didn't think it would be very useful for "real" boats.

 

I also saw a webpage recently (damn - didn't bookmark it) where a guy was building a folding tri, but used thin ply inside a male mould then glassed it, kinda like a foam and glass boat but using thin ply. He said it was very strong, very light , cedar frames I think.

[wheels 543]

However, there is possibly one way of doing it. But as a one off, it still wouldn't worth it. But for multiple hulls, hmmm, wonder why this hasn't been thought of. Maybe because there is a reason.

Biuld a complete mould for the hull and for the deck. You would need a male and female mold but with a gab between the two which would be your filler space. Bolt the two together and fill with the Polystyrene beads or whatever the base material is called befor it is activated and then activate. Which by the way, is just high pressure Steam injected in and the little balls expand and stick together. Density is determined by the amount you put in and a really dense material which is actually quite strong, can be made. The process would be about 2 to 5 mins. Remove the molds and you have a complete Hull to glass. Then simply laminated the Glass over it and then glue the deck to the Hull and you should have one heck of a strong lightweight Hull. Especially if you vacum bag and/or use Carbon.

Another variation on that would be to pour in the Urathane expanding foam. But I don;t think that is as strong. Dense Polystyrene can actually be stood on to work on. I don't think you could do that with expanding foam.

As i said, this method would require a decent double skin mold. And i imagine that would be expensive. But afterwards, I can only see a very fast means of making Hulls.

[Guest]

Your Fu*king dreaming,

 

you cant walk on the deck of thunder without wondering if you'll go through it.

the only thing holding it together is bog. good impact softness if your going hit the dock every time you come in tho.

 

There's no place for Plywood or Polystyrene in the marine industry

 

good for keeping your beers cold tho

[Guest]

 

There's no place for Plywood in the marine industry

 

 

A lot of John Spencer fans would disagree with you.

[Guest]

 

There's no place for Plywood in the marine industry

 

 

A lot of John Spencer fans would disagree with you.

 

that was last melinium, time to build new boats, not 30 year old shitters like most boats in NZ

[wheels 543]

Fullfoil, I think that reply shows your ignorance to materials and how they actually come together to provide strength. Learn about materials and the mechaincs of them before you make stupid comments like that.

So how is Polystyrene any different to Foam sandwich??? How about Davynicel?

So what or how would you biuld then??

[Clipper 343]

Wheels, don't bother with logic when talking to fullfoil. Just review one or 2 of his posts and you will see the intelligence and worrth he displays (on this forum)

[Guest Dry Reach]

I made plenty of windsurfers using polystyrene blanks i fashioned from old off cuts. but eh difference was that we built them to leave no pS in the hull.

 

We shaped the polystyrene, then cut it across the beam into three peices, then inserted Flanged "cut out" bulkheads (recessed into blank) faired mould / blank with Gib plaster (then waxed/ release agent) then layed up with glass and solvent free epoxy.

 

we only attached the bulkheads (while glassing) to the deck side for ease of seperation

 

when cured we ran the skilly around the area where the deck met the hull, seperated the two halves and pulled the blanks out and then glassed the two peices together (glueing the hull side of the bulkhead at the same time).

 

lastley we Faired them and the spray painted them.

 

And wallah! a light cheap hull and re useable moulds! and very quick.

 

Could do this for yachts as well and just make a recess for the hull deck joint! (and put ring frames in after)

[wheels 543]

I understand the concept with a windsurfer, but for a much larger yacht hull, you would have to use much heavier glass laminations and I think you would end up defeating the purpose of weight saving. Laminating with a light weight inner core results in the sum of the parts being much much stronger than the individual parts. Of course, it depends on how stress is "seen" on a part. So a particular fibre may need to be used to carry loads. For instance, Kevelar may be the material of choice for general impact resistance. But some exotic fibres may need to be included in areas where tension comes on for instance.

In the end, the materials used ina project and the way a project is made, comes down to Cost balanced with the ultimate requirement.

[w44vi 17]

some guys I know use poly for making 1m yachts

 

cut the poly to shape and bit of plaster to fear then glass

when the glass is cured put some solent inside , clean out the poly and plaster

 

easy

[Guest]

Like windwhackers a lot of the poly boats had timber stringers inlayed or laminated into them. Gave a bit of stiffness and places to fix fittings. The poly was only used to hold the 2 skins of glass apart in non critical areas.

 

Our last 18 was balsa core with lots of black sh*t stuck to the inside and clear finished something glass on the outside. She was last seen in the Maritime Museum painted Blue and branded 'Uncles', the now gone fast food place. And also the establishment the police picked up a rather pissed dude who was stark naked bar a bowler hat and umbrella and trying to order a peanut burger. He was the 1st person to be done on the Nth Shore for streaking and our forward hand on said 18fter. Also the designer of a few very fast sporties back in the day. Actually a 50fter of his is due to go splash in Nelson in the next month or so. But I digress.

[Guest]

Your Fu*king dreaming,

 

you cant walk on the deck of thunder without wondering if you'll go through it.

the only thing holding it together is bog. good impact softness if your going hit the dock every time you come in tho.

 

There's no place for Plywood or Polystyrene in the marine industry

 

good for keeping your beers cold tho

 

 

Oh lord..........nother ferro cement nutter ( rolls eyes skyward)

[wheels 543]

Oh lord..........nother ferro cement nutter ( rolls eyes skyward) :roll:

Hey...I resemble that remark

Nah he'll be a steel nutter. The type that thinks Steel is bullet proof, can leap tall buildings in a single bound, can sail faster that a Freight train and is completely unsinkable.

[MrWolf 0]

My old Javelin Hot Gossip is over 25 years old, is still down to minimum weight and is polystyrene core.

It needs looking after in that it is not very dent resistant.

 

But there are lots of old Polystyrene boats in the boat graveyard and that generally came down to a lack of laminate, you need enough to take the bangs and also to give some structure.

 

Another example of polystyrene (not so good this time) is the front beam fairings on Timberwolf when I bought it.

They always looked pretty banged up, when we took the beams off the two fairings weighed 80kg, they were fully sodden and waterlogged.

we replaced them with carbon and 6mm foam fairings that weighed less than 10 kg yet are still strong enough to stand on.

 

New core materials though are vastly superior to polystyrene (most new core foams are cross linked).