IDENTIFICACION

[fernando]

This HH example has a cylinder for 12 capsules with a considerable caliber (over 14 mm).
Could it be that 2 gr stands for 2 grains and not 2 grams. In any case, if this gun was made to shoot blanks, the amount of powder would be (much) less than for shooting a projectile; notwithstanding it needed to be noisy for the show purpose.
We ignore how these pistols were positioned in their niche; could be that they were introduced through some kind of orifice in that only the fairly long barrels stood out the boat hull, thus giving the impression of a cannon, as the HH caption seems to suggest.

[CSinTX]

Originally Posted by fernando

We ignore how these pistols were positioned in their niche; could be that they were introduced through some kind of orifice in that only the fairly long barrels stood out the boat hull, thus giving the impression of a cannon, as the HH caption seems to suggest.

Seems possible. The barrels do have a stepped profile similar to a ship's cannon.

Its probably safe to say that the trigger was pulled with a string. All examples have a loop at the bottom of the trigger for attachment.

[fernando]

Yes; not only the barrels of both examples have the same (cannon) shape but also their 'stocks' are made to mount in the same type of bed. Definitely both served the same purpose