After last posting I checked the paddle and actually the wall thickness is only 0,8cms as well - so it has 0,8cms wall, 1,5cms hollow, 0,8cms wall. I must have cut more than I originally planned while fitting the loom to my hand.

The loom is not oval, but rather a hexagone (6 corners) with rounded corners. The top and bottom sides of the loom are flat and it rests nicely on these - doesn't roll forward or back when I leave it across the coaming while getting a snack.

The dimensions you mention sound OK for WRC, as far as I can judge. Laminating the loom this way will probably add both stiffness and strength since the three pieces will have different runout and the flexing is stopped by the glue in the seam.

If you are planning on rather thick blades you should be able to extend the hollow far into them, and the paddle would be rather buoyant as well as light. I dont think I would taper the hollow in any way - what would the use be?

A thick loom can be light if hollow, and as diameter adds stiffness or allows for a thinner wall (George Roberts had some tables about this on his site, I recall - straightforward stuff) with equal stiffness, one can make as thick a loom as feels nice in the hand, and get the extra benefit of added buoyancy. Carving or planing the transition into the blades will be tricky though, as one at that phase no longer can see the hollow . And at that phase one has a tendency to want to remove more wood than might actually be available. (I had by then lost track of where exactly my hollow ended and had to rely on the plans drawn before cutting it!).

: I think I'll try that. The current paddle that I started on last night will
: be laminated up fairly close to the final shape - fewer shavings. Right
: now I have the center blank planed down to 3/8" think and thats as
: far as I got. The plan is to cut the center to the shape, and laminate the
: tip / edges to it. Then laminate the thickness, and carve it.

: It would be pretty easy for me to scroll, or rout, a center cutout from this
: initial starting blank. Leave 1/4" on the edges, and take 1/2"
: out of the middle, out into the blades? And taper it to a point? This
: happens to be a storm paddle, and I want it stiff. The laminations will
: add quite a bit to it that way and actually that center core part doesnt
: add any stiffness anyway does it? I'd get a hollow that is 1/2" by
: 3/8" this way.

: Nah, I'll blame it on grain run-out