Does anyone have experience with both buidling techniques? I am looking for advice on which makes a stiffer and stronger hull. Thanks
I’ve built a Pygmy Arctic Tern S&G
and a Redfish King strip. Which is stiffer? I suppose I’d give the nudge to the S&G over a strip built. A strip built boat, by its nature has some flexibility although slight. Plywood is not very flexible and S&G boats are stiff. Having said that, I really cannot tell any difference when paddling.
view from the peanut gallery
biggest differencs is skill and effort required to build (stripping is more difficult and time consuming) and the performance potential (stripping offers more varied possible designs). For a first project most builders I know would recommend a stitch and glue. Most newbie paddlers are not going to get all the benefits offerred by a top flight strip design.
Diclaimer (i’ve never built a boat)
stiffer or stronger than what?
usually people pick a kayak according to how it paddles. You can make it anyway you want.
Strip Boats
are, by far, superior to s&g, in my opinion.
In the end, it comes down to the quality of the build. Either boat can be built bombproof.
So far, I’ve built 2 strippers and 5 s&g boats.
I built a hybrid boat and…
I couldn’t imagine that you would be able to tell the difference in the ‘stiffness’ between a sng and strip boat that were built in the same manner. They are both really fiberglass boats, with a wood core…one core using laminated ply, the other stripped.
I am curious about why you are asking about the stiffness? My hybrid Night Heron gave me the opportunity to learn both sng and strip approaches. I am now building a sof, and will build a strip next.
Building boats has been a fantastic experience! Check out www.kayakforum.com for gobs of support/information, and you may want to raise this question there as well.
Enjoy…
Bob
Actually, the opposite is true
– Last Updated: May-09-06 5:24 PM EST –
The thinner, flatter plywood panels in most S&G boats flex more than typical strip-built hulls, which usually are thicker and curved, which contributes greatly to stiffness.
However, it's important to understand that stiffness does not equate to strength or durability. A hull's ability to flex - or not - when impacted can dramatically affect whether it gets damaged or not. A flexible hull spreads and absorbs impact energy over a large area, reducing the likelihood of exceeding the hull's strength. A stiff hull concentrates the stress in a smaller area, making localized damage more likely.
stiffness and strongness
Stiffness is usually an aspect of the design of the hull. Wide flat panels are not stiff. Sharp curve are. So if you want stiffness, don’t make a boat with a wide flattish bottom. This could be accomplished by having a highly arched stripper or a multichined S&G.
Strength is more a matter of the quality of the build and the decisions made on weight of materials. Many designs can be made too light. Most weak boats are heavy too, because they are simply not built well.
I’d go S&G for easy to build characteristics. Complete kits are available from pygmy, CLC, and JEMSwatercraft.com.
For ultimate speed and beauty I think a stripper is the way to go.
Is hot water wetter than cold water?
The strength mostly comes from the fiberglass. You can use multiple layers of light glass, or a single layer of heavy glass, or some combination and really taylor the stiffness and strength to your needs.
hot vs cold
My S&G is probably overkill on the keel tape& glass and the fact that the inside was glassed as well.
Yeah…it weighs more than 39lbs…But it’s like a timex watch…and I don’t regret the extra glass.
Looking back I might have incorporated a sacrificial copper or s.s. strip on the keel.
What do you prefer for …
Bulkhead material? 1/4" ply? 3/8? C&B strips?
Do you used foot braces or pad out the bulkhead for a foot rest?
I’m at this point now. I would like to keep the weight down but it has to be strong.
Thanks,
Bob
The question was stiffness not
strength. Both are equally strong I would guess. According to Nick Schade, author of “The Strip Built Kayak” the strip boat will flex more than a comparable plywood or fiberglass boat such as when hitting a rock, although I don’t know of anyone wanting to use their boat to test that theory! Sometimes the strips will flex as opposed to punching a hole according to him. I realize stiffness is relative and I think most people would have a difficult time discerning the difference in hull stiffness between a S$G and a strip boat. As stated above, the fiberglass is what gives it stiffness and strength.
There are many variables
in building a wood kayak to be stiff and strong. Plywood is very strong except at the seams. 4mm plywood is stiffer and heavier than 3mm plywood. 3/16" cedar strips are much lighter and stiffer than 3mm plywood. Cedar strips are very strong along their length but can break easily along the grain.
I build wood kayaks for their lightness. My last cedar strip kayak came out to weigh 10 lbs. less than my last 3mm plywood kayak with the same glass layup and it seems to be just as strong.
Any wood kayak can be made really strong if you don’t mind the added weight.
“stiffer and stronger”
“I am looking for advice on which makes a stiffer and stronger hull. Thanks”
bulkheads
1/8" ply bulkhead behind seat
yakima footpegs
float bag up front
compound curves in strippers
generally speaking a stripper can be built stiffer and stronger because the (possible but not necessarily) compound curves add stiffness from their shape. so stiffness goes to the stripper, stronger just depends on the build. at equal weights seems to me the stripper would in most cases be stiffer and stronger.
I always enjoy these threads!..
now that I’ve built one cedar strip kayak (Night Heron), well into a second, and I’ve assisted on two S&G boats.
There just isn’t enough difference in terms of structural integrity between the two styles to concern yourself with. The important thing to remember is that YOU have total control over the final product regarding strength and weight.
Slight flexibility has its positives in some kinds of impacts whereas a stiffer hull has its pluses in other kinds of impacts. Don’t sweat it. Ask yourself primarily this; are you more likely to have hard impacts in your paddling style or is abrasion a bigger issue? Both concerns can be addressed in the layup selected by the builder.
I often hear that the fiberglass (cloth & resin), provides ‘most’ of the strength. I disagree. If that were true and the wood core was simply an aesthetic aspect, then we could simply wrap some gorgeous burled veneer around the design forms and glass it all up. Actually, I suppose you could do this… but you won’t have much strength with such a minimal core. The 4mm plywood or 3/16-1/4" woodstrip core provides a great deal of the structural strength of a wood core boat. Thickness variations will, of course, have an effect upon stiffness and puncture resistance.
I built my NH with 1/4" cedar strips and I’m using 3/16" on the second build as the recipient is looking for light weight.
My primary consideration for the NH was abrasion so I wrapped her up with 6oz E cloth and added an extra layer of 6oz S cloth on the hull. The S cloth features greater abrasion resistance and is stronger overall than the E cloth. Downside is its not as pretty. Doesn’t wet out as clearly thus leaves a shadow or ghostly appearance.
I can stand on my NH aft of the cockpit with very little deflection (I weigh 165#), and it came in at 43# finished. Very happy with the kayak… and really glad its done as I’m a bumbling woodworker!
Stripper or S&G, doesn’t matter. They’re both a great way to build a strong attractive boat customised to YOUR needs. After you do one you’ll find it very difficult to be satisfied with a production kayak or canoe again.
Good luck to you and have a great build!
Holmes
Have to go along with…
“I often hear that the fiberglass (cloth & resin), provides ‘most’ of the strength. I disagree.”
My first build was an 18’ racing catamaran with 3mm ply and NO GLASS, just epoxy and some fillers. That boat held up quite well for quite a while. It was not bombproof but it was light.