I was browsing my local boat store the other day and noticed a plastic Boreal Designs tandem. Two design features struck me.
First, there was an internal reinforcing “keel” (if that’s the correct term) made of 1 1/2" or so diameter aluminum tubing running the length of the boat. I’ve seen these in cheap plastic kayaks but never in a kayak.
Second, there was no rear bulkhead for the center storage compartment (i.e., the center compartment was continuous with the rear cockpit).
Am I correct in thinking both of these are indicative of cheapness in design?
(Just to be clear, I’m not in the market for a tandem; just curious.)
The keel reinforcement just testifies to the difficulty of keeping the bottom of a plastic tandem stiff enough for decent paddling. My main concern would be that they have that aluminum tube solidly located in the center.
As for the lack of a bulkhead, does that mean there was no center hatch? Or maybe it’s just their way of providing for very tall stern paddlers with size 15 feet, like mine.
plastic doubles can get waffly I can’t say if that design is cheap but those characteristics don’t necessarily indicate cheap as in low quality.
If a double is long enough you might as well section off the middle for more flotation as the amount of free water is HUGE and complicates rescues more than singles but there’s a limit as to how long you can make a plastic double for weight and structural reasons as they’re already tanks.
There you go,don’t know. I’d consider making a small wood double before buying a plastic double.
my reading is that there was a center bulkhead but not a bulkheaded flotation compartment in the middle. There are fore/aft compartments. There is an option of adding a childs seat and creating a small enclosed compartment.
My $.02 is that although no flotation would be catastrophic in a double but it's really not that great with what's there in the ends compared to the free water in the middle.
this is the double I paddled and saw some guys dump just outside the surf zone. It has fore/aft compartments and a single minicell bulkhead in the middle. The amount of water in the cockpits is so great that they could not keep it upright or prevent it from shipping more water in 2' waves. When it finally tumbled to shore it took four of us just to roll it on it's side to pour the water out. It felt like a ton of water. Seriously on a sloping beach it was very hard to roll downhill to pour the water out.
It reinforced the idea why doubles are extra stable, they're like rec. kayaks, if you're dumped in waves you're screwed.
Polyethylene is not a good material for making long boats -- it's just not stiff enough. Rotomolding makes it diffcult to add molded features that would improve stiffness. The aluminum rod is a way of adding stiffness that saves weight -- without it you'd probably have to add several pounds of plastic to get equal stiffness.
Several plastic kayaks use metal tubes or composite beams to enhance stiffness. It's just another way of dealing with the inherent softness of the plastic.
Polyethylene's virtues are impact resistance and low cost. It's a poor choice for making large rigid structures.
A tandem without a center compartment gives you lots of rear legroom and packing options, but it'll be a nightmare to self-rescue. Sea socks for both cockpits would help.
an electric pump in both cockpits we had a hysterical time trying to self-rescue that plastic WS Northstar. One guy scrambled in and tried pumping out sitting in a swamped cockpit while the other guy held on by the outside. There was no way he could remove enough water in the few seconds before the next wave came by,maybe if both of them were inside bracing and pumping at the same time but I seriously doubt it. Once the wave lifted them up the boat rolled like a huge half submerged ship in slow motion.
Maybe you other folks have had success but it wasn’t anything like the rescue practice I did in flat water or little chop. Actual waves (not breaking) are something else.