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Old 23 December 2006, 12:50   #21
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Like A Gong . Oh Yes they do, like a alu drum. Every time you hit a wave.
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Old 23 December 2006, 12:56   #22
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Rotomolding is good for kayaks and small boats (up to say 10' long). You can't compare a PE boat to a GRP or a Ally boat.
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Old 23 December 2006, 13:41   #23
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Quote:
Originally Posted by Polwart View Post
Roplene is a trade name for a "rotationally mo[u]lded polyethylene" which is the same material most of these boats are made from - in the same way that all "grp" boats are made from glass reinforced plastic. There will be different grades of material - but generally they will be similar. I suspect the problem you describe is not fundamentally with the material - but with the design. Anyone buying such a boat (or indeed any outboard powered boat) should pay attention to the mounting of the transom to the rest of the hull.

Questions also need to be asked about hull thickness. A similar deign of boat typically has a thicker plastic hull than it would in GRP. Cutting down on thickness saves the manufacturer money (particularly in times of high oil price) and he may even say the boat will go faster (as it is lighter) - but has a dramatic effect of rigidity/flexibility.

Some of the manufacturers offer reasonably long garuantees on the hull integrity because they are so sure of the material/design.

Fixings take a little thought - as they would in an ally or grp hull though. If the manufacturer knows where a part is to go he can mould the nut/fitting into the design, if not it needs appropriate backing - and to be fitted in a suitable place in the boat. As the material is "slippy" - self tappers may be even less appropriate than in other boats.

You can repair the material by welding - its is a specialist skill though.

Pathalla there are plenty of under engineered GRP hard boats on your side of the pond - if you saw them you could equally say "never buy a GRP boat". One bad apple and all that...
Thanks for the info on the Roplene Polwart, something I am not really familiar with, This boat did seem somewhat shabby in construction, the components of the center console seemed too thin and the hull looked as if was pulled too soon (while soft) from whatever/however it is built. The slipperiness of the base material did seem to present a real problem in relation to how well it held fasteners, The owner had fasteners constantly working out of the Roplene, I personally think it deforms too readily from it's original shape from stress, if it was a lot thicker maybe not, but I will stand by my original contention, inferior to glass or metal. Just my opinion, and I respect yours and your knowledge on the subject, Merry Christmas to you and yours!
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Old 23 December 2006, 13:42   #24
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I drove both Ali ribs and GRP ribs when I was working in the North Sea last year and I can certainly confirm they do be noisy.

I prefer GRP especially for domestic purposess because you can (if needed) repair a hole on a beach and you can carry the repair materials with you in a waterproof tub.
I am also fairly convinced that the hull shape of a GRP plug is easier to refine
so they ride the water better.

Having said that it's difficult to ignore the craftsmanship that goes into an Alli boat. If the boat was to be used as a workboat maybe Ali
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Old 23 December 2006, 13:48   #25
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Quote:
Originally Posted by jyasaki View Post
Logic and Triumph both build boats from Roplene (co-owned companies, I think.)

From the Triumph website: "Most boat hulls are rigid and stiff as boards, creating an uncomfortable, jarring ride. On the other hand, the shock-absorbing Roplene hull of the 195 CC soaks up the impact of every wave. The result? A ride so quiet, soft and dry you have to experience it to believe it."

So, apparently the flexibility is a selling point (though I have also heard that their ride is not all that great.)

The reports of problems from the softness of the plastic and such that Pathalla mentioned are apparently pretty widespread. A buddy of mine has a 19' Triumoh, and is constantly trying to lock screws in place.

Don't know about the comment about low-ish power limits; the Triumph line has a max HP rating of 150 for their 19', and 250 for their 22, which doesn't seem that far out of line.

jky
My buddy's boat which I believe was 21 foot had a terrible ride, harsh. It seemed kind of flat on the bottom for a vee hull, I don't know if it was made that way or if the hull started to flatten on the trailer because it was too soft. Either way not anything I would ever buy or recommend.
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Old 23 December 2006, 13:49   #26
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Quote:
Originally Posted by Endeavour View Post
Rotomolding is good for kayaks and small boats (up to say 10' long). You can't compare a PE boat to a GRP or a Ally boat.
Quite right

With a PE boat:

- You don't need to antifoul (apparently) as nothing will grow on it
- If you hit something with the hull it bounces off rather than bending or cracking
- No tubes to go pop every other trip by themselves or if you hit anything sharp, or need cleaning all the time

Still unsinkable
Still looks like a RIB (well the one I want does, anyway)
More deck width (on the Mac 570) than an equivalent beam of RIB

It appears that you get to spend more time boating and less time fixing/cleaning which can only be a good thing with 9 months experience of a rib under my belt

There is something sexy about anything made of alli though...
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Old 23 December 2006, 14:00   #27
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PE Boat??

Hi Steven. Has LandRover done a deal with Tupperware ?
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Old 23 December 2006, 14:04   #28
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Quote:
Originally Posted by fast fred View Post
Like A Gong . Oh Yes they do, like a alu drum. Every time you hit a wave.
Fast Fred, Are you jerking Jyasaki's chain? C'mon... I have an aluminum boat and it doesn't make any more or less noise than glass boats do, actually most of the time all you hear from any boat is the hull cutting the waves or the occasional "bang" when coming off a big wave, if it's well constructed that is. What he has is very well constructed, Polaris. Actually, although I like both glass and aluminum as a hull material equally well I do tend to think aluminum is somewhat better because it can be welded, no rot and it is very tough properly put together, I know mine is, very tough...
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Old 23 December 2006, 16:26   #29
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Quote:
Originally Posted by Endeavour View Post
You can't compare a PE boat to a GRP or a Ally boat.
Its a bit dumb to say that - it is precisely what people were doing!

Your comment suggests they are either completely diferent kettles of fish (like comparing a 6m rib and a 20m cabin hardboat) or that one is outstandingly superior to the other. There are pro's and con's of both options. (One pro steven missed off his list is price!).

Comparing them is quite logical since they are "marketted" towards similar applications.

Oh by the way I am a rotomolded boat owner - but will probably upgrade to a real rib when funds allow.

Quote:
Rotomolding is good for kayaks and small boats (up to say 10' long).
you are welcome to try my 14' boat - I think you will find it performs as well as you would expect any similar sized rib (with similar hull profile). I contest that the popularity for rotomolding smaller boats etc is that the cost benefits are much more apparent then.
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Old 23 December 2006, 16:32   #30
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Quote:
Originally Posted by pathalla View Post
the components of the center console seemed too thin ...
... The slipperiness of the base material did seem to present a real problem in relation to how well it held fasteners, The owner had fasteners constantly working out of the Roplene,
I recognise with these issues (my console is fine - but the seat/locker lid is too thin (about half the hull thickness) and flexes slightly under my fat ass. I like to kid myself on that it is like a mini ulman - as I bounce up and down on it! I only have 2 self tappers on my boat for this very reason (they hold the bilge pump bracket in place).
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