Plastic vs. Composite Speed

Accepting the general consensus, that composite boats are faster than poly. I’m curious to know if anyone has actually paddled the two of the same model. For example, numerous threads mention the VCP Aquanaut as a fast boat, but does anyone have experience paddling both the Glass and Poly versions? And if so, can you tell a difference in speed (a lot, a little, a guestimated %, not at all)?

Gulfstream and Sirocco
I used to paddle a Gulfstream almost exclusively and borrowed a Sirocco for a weekend from a friend.



Although there were some differences in the two boats, I did not notice any difference in speed between them. Perhaps if I was trying to race, there would have been a difference, but not in ordinary paddling.



What I did notice the most was that the plastic boat rode higher in the water and as a result was more affected by cross winds.



Also, the cockpits were slightly different in size and my normal neoprene skirt, would not fit.


Have a Sirocco

– Last Updated: May-03-06 10:03 AM EST –

and agree, very much affected by winds. For me, it handles better loaded, but still - I believe it's really too voluminous for my frame (5ft-10in, 180lbs).

you
won’t really notice any hull speed differance, but you will notice ease of paddling. the glass versions glide better…hull speed is determined by shape etc…if any two boats are the exact shape (which they really aren’t) their hull speeds driven to their designed hull speeds will be the same…at the end of a day, after paddling both, you will have gone the same distance but have more energy left to do other things after paddling the glass boat. also when taking pictures…you will notice that the plastic boat stops in a relatively short time/distance after you stop paddeling. The glass boat will glide farther after you stop paddeling, causing you to run into other boats etc while expecting the boat to stop.



The plastic boat can take a beating, but the materal lost, is not replaciable, whereas the glass can be refurbished for many many years. glass can take much more of a beating than commonally thought by people new to the sport



Hope some of this helps and doesn’t just cloud the issues



Best Wishes

Roy

Not the same
Often, as in the case of the composite and poly Aquanaut, the hull measurements of the boats with same model name are different. So, one cannot assume the same performance even if the material does not make a difference.



Sea Kayaker’s drag figures note adjustment made for plastic hulls. It seems as if they feel there is a difference.


wait a minute
no speed diff but more ease of paddling and glide?



one of the six degrees of freedom is SURGE. either a boat is free to surge or not. The freedom to surge IS speed and ease of paddling AND glide WILL result in a higher speed, given EQUAL motivation.



steve

yes
while the discussion of the CD Sir vs GS is comparing red apples and green apples (similar but NOT the same) I have done extensive tests on Tempest and Tsunami models (f/g vs roto) which ARE the same. We strive to duplicate our designs in each material, exactly.



Off the showroom floor the boats are so close it is impossible to tell ANY performance differences, speed, stability or YAW. when the roto boats get a few miles and scratches on 'em all bets are off, tho quite insignificant, IMO.



steve

hull is different
the scirocco weathercocks more and the skeg isn’t as effective compared to the Gulfstream. I’m not sure of the exact differences in the hull but they’re there. The Scirroco glides through the water just as efficiently as the Gulfstream but there’s something different about the hull shape that makes it weathercock more. It’s a bit more “v” and I think that v extends further forward than the Gulfstream. I wish they corrected that because the general design is worthwhile.

yep
I like how the T-165 handles compared to the T170 with my 200lbs. And the plastic/glass versions are similar. One thing that’s curious is how rounded the plastic T-165 entry is compared to the plastic T170.

All the same?

– Last Updated: May-03-06 10:51 AM EST –

Peter O. posted that he had tested a FG and poly version of a P&H boat and found no difference in avg. speed over the same course. I have heard people say they find little if any difference between the FG and poly Avocet in terms of performance even though they are different is some areas in terms of size. I suspect there is a difference in the "personality" of FG v poly versions of boats that people say they can feel. Whether that is something one can measure objectively or not is another question.

Understood
I do know there’s a difference in the hulls, so an exact apples to apples may not be possible. But your general perceptions of the two, to the extent comparisons are valid, are what I’m looking for.



Roy’s comment about gliding was helpful as well. Not a whole lot of that happening in my boat.

I

– Last Updated: May-03-06 11:13 AM EST –

figured that the question pertained to designed hull speed for a given shape, not motivation....

two boats with the same shape showing to the water will be the same optimal speed before they hit the wall....scratches and dings were not in the equation...but even if they were...the two boats would have the same optimal speed before hitting the wall....doesn't say how much work each takes to hit it's optimal hull speed or wheather any paddler in question is physically fit or motivated to paddel any hull to it's optimal hull speed

sorry for any confusion, I was just trying to answer the question as stated

I thought that the question was which boat is faster, not which one are you capiable of paddeling faster

Best Always
Roy

poly vs. composite hulls
Someone from the staff of the Kayak Centre in RI explained it to me this way: the paddler in a composite boat can expect to be @a nautical mile behind a clone of him/herself in a composite model of the same boat at the end of a long paddling day. Also, in five years, the poly boat will not be the same boat; the hull will have deformed to some degree and the fuzzy scratches etc on the hull add to surface area & drag in the water. Paddling a poly boat vs. a composite could be likened to paddling a bicycle with tires inflated to 20-40 psi (poly) to a racing bike with tires inflated to 75psi-100 psi ; the poly hull gives a little more with the water, transferring more of water’s energy into the hull. Poly hulls, of course, vary in their rigidity/quality etc from one manufacturer to the next. Valley seems to have very robust poly hulls, and the Avocet might be the piece de resistance of poly boats…

No experience, but it is common sense
That if two boats are the exact same, but one is made out of heavy poly and the other is lighter composite, then with the same engine the lighter boat will go faster.



cheers,

JackL

accelerate faster
not necessiarially have a faster hull speed…you now changed wetted surface and waterline…except on plumb bow boats, none of which have been in the mix of poly vs glass.



also depending on the year and models we are talking about the plastic might be lighter than some glass boats of the same model…catalog only lists a 6 pound differance at present



Glide is still what you will notice the most



Best Wishes

Roy

Scratches or dents
I’m thinking that (severe) dents and oilcanning might make the biggest speed difference, maybe even change handling.



My T165 has some scratches, all garnered on camping trips. But it’s holding its shape very well.

Not motivation
You didn’t miss anything. My question was aimed at determining whether or not I’d be able to tell the difference between boats of the same hull design, but of different materials.



My intent on referencing speed, was framed (in my mind) around me putting the same effort into each boat. That effort being, what a normal (distance) paddeling rate would be for me, but not sprinting over a short distance. In other words, whether or not I’d notice a greater distance traveled per hour, given the same effort being put into each boat.



Dave