Polycraft of Australia makes an interesting range of what they call roto-moulded polyethylene boats.
Polycraft claims...
--5 times as resistant to impact as fiberglass.
--Dual wall construction and moulded without seams, joins, or welds.
--not affected by electrolysis (aluminum is) and osmosis (fiberglass is)
--uv stabilized marine grade polyethylene used does not fade and never needs painting.
--four year warranty for pleasure use, one year for commercial use.
Did you previously say you were discouraged about polyethylene boats?
I can not remember...
having expressed any doubts about high density polyethylene (HDPE) other than performance. The advantages you are mentioning are all perfect arguments for the use of HDPE, the only problem is transfer of the forces produced by the engine into overcoming the friction of the water and the boat. The harder the surface (polyester for instance) the better the transfer. So it is really a question of priorities. Also remember that a lot of friction reducing waxes and coatings will not stick on HDPE.I designed a dozen or so smaller boats (from Bass boats down to kayaks) all in HDPE but I would not pretend that they are designed for high performance...than again I would prefer a canoe or kayak to be designed to fit the kind of water that you want to navigate (large lake, small lake, river, white water etc. rather than getting the highest performance out of the boat. Impact resistance and U.V. resistance are indeed very high. I see here on the lakes boats that we designed 15 years ago in perfect condition.
About HDPE's relatively high friction with water...
Ride quality in boats has always seemed more important than top speed to me.
Most boats will do 35-37 knots with the right motor, which is plenty fast. Going 40-55 knots has always seemed kind of purposeless for most boating activities. Fast to no particular end, but fast. Its okay to have a few fast boats, but most center console skiffs really don't need to go 55. The crabs and tuna are going to be there no matter what speed you go.
One review of a 16' HDPE raves about how wonderful the ride of an HDPE boat is. The builder, Polycraft argues that designing flex back into boats with HDPE is good. He makes it seem analogous to designing flex back into bicycles after they got too stiff. This has me excited, especially now that they are making HDPE skiffs 16 to 20 feet in length.
Is it the flexing of the HDPE hull, or the surface of the HDPE hull that causes the friction?
Can you imagine any solution to reduce the friction of HDPE?
koen, tell me the names of some of the boats you designed...
If you designed a 14-18 feet or longer bass boat, or center console skiff, I will look for one on the net. I like to buy used boats, so one from the 80s or 90s would be fine with me. I need one for crabbing in an Oregon estuary. If I can find one of yours on the net, I might try to buy it. What could be better than a Koen Kraft!! Maybe I could get you to design me a little Koen Kraft logo and I'll mount it on the sides of the boat. This could be fun. A designer bass boat!
There is nothing wrong...
with the friction of HDPE and water. The problem with motor boats is that the polyethylene is not stiff enough and so a lot of energy is absorbed by small mouvements of the hull. As I said before it is only important for high performance...and energy saving...
As mentioned before, I only did small boats. The largest one was 10 feet.
I will include the link to that one from there on you can navigate Pelican International's website and see all the others. With the exceptionof a few we designed all of them.
http://www.pelicansport.com/index.php?language=en&category=fishingboat&n...
Those are among the neatest small boats I have seen...
How did you decide on a modified V hull, or what I would call a tri-hull, or a cathedral hull (Chrysler's old marketing name for the early tri hulls in USA).
Would this design be capable of being stretched out to 15-18 feet in HDPE, or would a longer boat made of this material require a significantly different hull form?
I am jumping up and down on my chair again! This is terrific to talk to a boat designer, regardless of the size of the boats. Did your group design this ten footer, or did you start with a hull design from a "marine architect," the upscale term a lot of boat builders are using these days?
Also, wouldn't one of your little 10' tri hull bass boats be a kick with this little electric outboard with claimed 6 hp equivalent power?
http://directboats.com/tocrelou.html
Hi DC
I will have to wait untill tomorrow night before I can answer your questions...sorry.
You might have noticed on directboats.com that Pelican International and Coleman are the same. They are not copying each other it really is the same product from the same manufacturer, but Pelican has a license to use the Coleman name for their products in the U.S.
...no I did not work with a naval engineer or architect. This is not America's cup material...and I am obviously not Bruce Johnson (at Sparkman & Stevens)
15 foot Whaler
I've been searching the web for information on my 15' trihull and bumped into your thread. I've had some trouble finding anything on HDPE except Logic Boats. I sent them photos of my boat and they were caught by surprise by it. They had never heard of or seen a boat like mine, now here you guys are talking about boat design and building (and buying) exactly what I already have. Admittedly, it is over 10 feet so not designed by you or likely built by Pelican. It is an EXACT duplicate to an early 15 foot Boston Whaler, right down to the anti skid surfaces on the deck. It is the most awesome boat I've had in 40 years of boating. I have an old 60 Yamaha on a tiller control and top speed is 32 MPH. It is very heavy and combined with the flex and movement I understand is one of the HDPE boat characteristics, it is an extremely comfortable ride. My kid takes it out with his buddies and their boats, usually with much more power on them, as soon as there is any chop or waves on the water, he leaves them well behind.
So? being in the boat design and building business! Any idea who or where a 15 foot HDPE Boston Whaler might have been made?
Greg S
Vancouver Island
British Columbia
Canada
This is an interesting mystery...
Perhaps you have a boat imported from elsewhere by an individual, say, a Polycraft from Australia, or something like a Terhi from Finland, though neither of these seem like direct knockoffs of a BW.
I hope someone can solve this mystery. I can't. Mr. de Winter grows rather encyclopedic in his design knowledge about whatever he designs, though his main bag is not boat design. Perhaps he (or someone else here) might have stumbled across an HDPE Whaler clone.
Regardless, you have very nearly the boat I want! Or maybe I want one a foot longer with a diesel outboard. 🙂 Yan Mar quit making their legendary 15 hp outboard diesel and so we have been in a diesel outboard eclipse now for awhile that will reputedly lift quite soon, because of high gas prices, the coming ubiquity of low sulfur diesel and biodiesel, and advances in exhaust management regarding diesels, but I digress.
Please post here, should you solve the mystery elsewhere.
Greg S...Atlantic Focus boats of Germany...
Their center console 4.5 seems pretty close. Perhaps someone brought one of their boats into Canada. The link below is to their page on the boats pictured below. The link farther down is to their discussion of roto moulded Polyethylene boat construction.
http://www.atlanticfocus.com/450%20PAGE.htm
http://www.atlanticfocus.com/450%20PAGE.htm
Close but not quite.
That Atlantic Focus boat is close, but not quite. It looks good but is about 500 pounds lighter. I bought mine as a bare hull with no seats, cleats or anything, not so much as a screw in it yet. I took it to the nearby government truck scale and weighed the bare hull. It was 900 pound with just the hull and flotation foam. Then I added seats, cleats, motor and ancillaries. I doubt it was imported, but may have been. It was one of 12 or 14 that were going to be used in a fishing charter business that never left the shore. None of the boats ever progressed beyond the bare hull stage. I bought it off a guy who claimed to be the original owner (but I have my doubts) He sold the whole lot off at about $500 each. Mine is the only one I've seen that is finished and in use. I bought it almost 10 years ago. Now, if I could learn how to post a picture here.
Greg S
Also consider Neveux...
Atlantic Focus boats of Germany and England says that a manufacturer named Neveux builds their Roto molded plastic boats. Perhaps Neveux is French and someone imports their boats into French speaking Canada. I had no luck locating a Neveux web site on Google, but discovered some of their kayaks for sale.
Greg S...I believe it is the outboard equivalent of...
gasoline cars running on ethanol with flex fuel engines. I doubt it is an actual diesel, but I will look anyway.
Many boat engines are getting harmed by ethanol laced gas, as have been reputedly many car engines. In fact, probably the largest motivator to spreading ethanol gas is NOT to reduce dependency on foreign oil (note: the amount of oil you avoid by lacing gasoline with ethyl alcohol is probably a net negative when you combine ethanol's reduced mileage and power per gallon plus the HUGE petroleum inputs to grow the grains use to make ethanol). The function of ethanol is to accelerate the destruction of legacy engines in all applications and force us all to buy cars, trucks, boats, etc. It is the vehicular equivalent of Microsoft bringing out the next version of Windows; it finances the multinationals' maintenance of their oligopolies.
The new cars will burn a little cleaner and use a little less fuel, but the technological "improvements" unrelated to ethanol built in to the new cars, trucks and boats, will actually expand the carbon footprint of these vehicles. The point of ethanol is to stimulate/force new consumption in a US domestic market that is saturated with cars and which faces buyers with declinging real incomes. Ya gotta make'em write the checks and divert a greater percentage of their shrinking income to the vehicle makers.
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