: Not all boats need the same thing since environmental conditions
: vary. How the boat is handled is a factor also.

: When I bragged to Uncle Jay that my Outer Island came in a 30.5
: lbs, the first thing I heard back was concern expressed about
: strength. I figured he lives where rocky shorelines are the
: norm, whereas I must literally drive 200 miles to see a
: naturally occurring rock; it's all sand and mud bottoms around
: here, no chance of any seal landing shenanigans. And a few hard
: seasons later, sure enough, no hint of a problem with it. The
: wise builder (and me too) takes external conditions into account
: when engineering the strength factor he needs -- and every boat
: is an assembly of compromises.

: I'm more than a little surprised at the comment saying sooner or
: later everybody loses a boat. I guess we all know WW people are
: half loco, and/or bounced their beans off rocks a few times
: (speaking of rocks again), maybe that's the deal. But I've never
: come close to losing a boat, nor believe it's any kind of
: inevitability. If you use proper rack systems and proper
: tie-down practices, you should never have a problem. The better
: the cradles fit, the less cinching down is necessary (ratchet
: straps -- OMG!!). I just barely snug my boats down, but use only
: top-quality (Yakima) straps.

: Sermon over, hallelujah!
My first build was a CLC Shearwater S&G. I followed the instructions implicitly, and the boat came in at 44lbs. The instructions called for a full layer of 'glass on the bottom, a "football' shaped piece on the bottom, two reinforcing strips at bow & stern, and all panel seams done with substantial fillets and 9 oz. fiberglass tape. I remember thinking that there was a little "overkill" in the instructions.
My second build was a Shearwater Hybrid. I skipped the "football", kept the fillets slim, and cut my own strips of 4 oz. 'glass for the seams. It came in at 41 lbs. I did once have to beach it on rocks, and it escaped with only scratches.
Yes, Who Uses It, How and Where are definitely major factors in the construction. I think that because I have been sailing much longer than kayaking, I have a strong instinct to give all rocks a wide berth.