The vertical stanchions of the bow railing for a 1978 REVENGE 21 attach to the outboard side of gunwale of the hull the widest points. The beam of the hull is listed as 7-feet 4-inches.
The vertical stanchions of the bow railing for a 17-foot hull--there are many models of 17-footer hull but most of them share a common foredeck arrangement--attach to the hull on the inboard side of the gunwale and to a lip on in the cockpit molding. The beam of the hull is listed as 6-feet 2-inches, and the railing is at least three or four inches inboard on each side
BuddyRoeaux wrote:Would a [bow railing designed as a replacement for a] 17-foot classic bow railing [attach to the hull of a 1978 REVENGE 21 ] in the same mounting locations?
The bow railings attach at different places
BuddyRoeaux wrote:...is the 17-foot replacement bow railing too narrow [to fit on a REVENGE 21?
The hull of a REVENGE 21 has a beam that is 1-foot 2-inches greater, and the attachment point of the vertical stanchions are place farther outboard than on the 17-hull by perhaps six-inches. On the basis of the dimensions for the beam of hulls and the location of the vertical stanchions on the hull, the bow railing designed to fit a 17-foot hull would probably be be about 1-feet 8-inches narrower than the bow railing designed for a for a Revenge 21. Also, the number of vertical stanchions and their placement is different. The REVENGE 21 has eight vertical stanchions; the 17-foot hull railing has five vertical stanchions. Also the bow railing for the REVENGE 21 has a bulge outward at the bow centerline.
I suggest you take the broken bow railing to a marine fabricator and have it repaired or used for a pattern to fabricate a replacement. You could probably re-use many parts of the broken railing, such as the unusual bases for the vertical stanchions.
BuddyRoeaux wrote:Where can I best find replacement railings for a 1978 Revenge 21?
I doubt there is any vendor who has an inventory in stock of OEM replacement bow railings for a 1978 Boston Whaler REVENGE 21. It is not exactly a common replacement part. It would be rather odd to find a fabricator who keeps in stock parts for a boat that is 43-years old and was not exactly a best-seller when it was offered.