Apparently Kolstrand has gone out of business (see comments below).
Another recommendation passed on by Dan Gill (Backyard Boatbuilding mailing list).
Kolstrand Marine Supply is a Seattle based supplier of fishing boat gear. They have a small website with a few things online and a PDF catalog (a scanned copy of their paper catalog).
According to Dan:
…if its used on a fishing vessel, they have it.
No frilly yacht stuff. Just heave duty stuff in Bronze, Stainless, and HDG that has proven itself in such harsh environments as the Aleutian Islands, Bering sea, North sea where peoples lives and livelyhood depend on it working day after day. They are strong on hydraulics, too. …
The people that answer the phones there are very helpful and glad to take some time to go over things with you. Many of them are from fishing families and have used what they sell. Anyway, if you are trying to find some heavy duty stuff for a serious powerboat, give ’em a call.
800-334-3224 Toll Free