I don't know the official answer to your question, so I'll just give you some random personal opinions.
Case "gunboats" or "big gunboat canoes" (pattern # x394, I think) not only have more and different blades (usually spear main, sheepsfoot, and spey) than a "regular" canoe (spear/pen), but they have a bigger frame (4 1/4" compared to 3 5/8"). How big is your Hammer Brand 4-blade canoe?
My personal "habit" is to call any knife with a canoe frame of any size and 3 or more blades a gunboat, but I often don't know what I'm talking about. Here are several examples:
Rodgers-Wostenholm 1978 NKCA 3-blade canoe: 3 5/8" closed, spear/spey/pen blade combo. I call it a gunboat, but online I think it's most often called a 3-blade canoe (but who knows how much expertise the various posters have?).
Frank Buster Fight'n Rooster 4-blade canoe: 3 5/8" closed, spear/spey/pen/coping? blade combo. I call this one a gunboat, too, but online it's often called a 4-blade canoe, or a gunboat, or a 4-blade gunboat. In size and blade selection, this is like your Hammer Brand, I think.
Rough Rider black-lip pearl gunboat canoe: 4 1/2" closed, spear/spey/sheepsfoot blade combo. I think this is called a gunboat by me and everyone else who's aware of its existence.
Notice that in terms of blade placement, the first and third examples (and Case gunboats) are similar to a stockman, with main blade and one secondary on one end, and the other secondary on the opposite end. But I've seen some 3-blade canoes that have the blades arranged as a whittler, with main alone on one end and both secondaries on the opposite end; if such knives are regular canoe length, or smaller, they're of course called canittlers.
Here's an interesting 4-blade Case canoe I stumbled upon tonight:
https://www.casexx.com/Library/HistoryHandleBook/HistoryDetails.asp?ProductCode=1602N
That Case, your Hammer Brand, and my Fight'n Rooster all have 2 blades (big and small) on each end, a configuration of blades I associate with a congress pattern. But I don't think there's a genuine sheepsfoot blade among the 12 blades on those 3 knives, which is very UNlike congress knives. So maybe I'll just refer to those knives as "sheepless congress lost at sea". Think that will catch on?
- GT
