Can a cargo ship have a .177 as a deck gun? Liberty ships had a Stern-mounted 4-in deck gun for use against surfaced submarines as it is listed in online Wika page.
In Big Gun, you can arm any 3 inch or bigger gun. When I say can I mean you legally can of course. Fitting them in is a different story...
For a larger cargo ship fitting the deck cannon should not be to difficult, you already have extra room. Now whether they can rotate and how many will be limited on your ability to build. I have seen one guys cargo ship have a single rotating bb cannon to help plink holes in attacking warships to help score more points but other then that a regular cargo ship cant do much significant damage. Now if you built say a German raider, that could be deadly.
When the NABS club was active we made rules for German raiders and Allied Armed Merchant cruisers. Eric Broderick, one of the original club members, made hull molds for a couple of the German raiders and sold several. We allowed them to have 1-2 BB canons depending on theirsize and armament. Cannons were restricted to bow and stern arcs. I don't think we allowed pumps but on the other hand I never saw one completed as a combat ship. A couple were built as targets.
I build one of the Komit hulls. Quite small & relatively unstable. Would need to be treated similar to a destroyer in order to be feasible. I can't see the effort being worth if for such a slow boat.
I remember the Komet hulls were surprisingly deep for their small size. They would require a lot of ballast to float at scale waterline. If not ballasted enough they would be quite unstable. About 4 Komet hulls were sold in the Maritime provinces but I think only John Coffill's was completed as an RC model. It was an unarmed freighter and was a bit unstable, riding high out of the water. Eric Broderick also made hulls for the mid-1940's MV Pundua, a Victory Class sized British freighter. John built one of those too - it was used frequently as a target ship and for some reason was called "the school bus". Eric made hulls for an American troop transport (I don't remember the class but several hulls were completed as the Bogue class CVEs). Eric built a beautiful RC combat model of the Bogue but it was so nice I don't think he battled with it.
Basic transport armament is not particularly effective due to its light weight. Sure you can plink with it, but it does not discourage attackers. The raider idea has much more potential. I have yet to see anyone build a raider for Big Gun, but the general consensus was - if you install raider-level armaments, it can be either an armed raider (heavily-armed warship, no cargo points), or an unarmed transport (guns switched off but scoring cargo points), but not both. You would have to notify the combat director prior to commence fire whether your ship would be acting as a warship or transport. The advantage is that potential opponents don't know if they are pulling up alongside a defenseless target, or a torpedo-armed ship-killer, until the first shot is fired. It would be even more effective with several on the water at once, with similar paint schemes. It is a very appealing idea, but most people end up building regular warships instead.
