The marines can then be dropped off at a contested wild island to hold things down until the Marin can come and pick the gold up.
That’s the hope, but stuff like that has never really worked for me. The Marine doesn’t prevent a ship with 2+ masts and explorer from coming in and grabbing stuff, then leaving before the Marine can get a second shot in. (assuming the first even hits) It helps to have 2, but it’s an awful lot of points to be paying for a couple of mobile 2S cannons that are easily avoided or taken out.
I think the “extra cannon crew” would have been a lot more viable and interesting if the original pricing had Musketeers at 2 and Marines at 4. Or even 1 and 3 or 2 and 3. Musketeers are not that great, making the premium Marine version even less effective, to the point where I’ve found them to be somewhat useless. To make them worth 6-7 points, they would have to both prevent explore actions and have a 2L or 3L musketeer for “sniping” that eliminates crew, in addition to the regular 2S. Even then they’d be risky compared to an extra gold runner or for example a world-hating captain.
This fleet will go up against Barbary Corsairs and a Jean Laffite-led swarm fleet soon.
Yikes. Though perhaps the Marines will be good against 1 masted gold runners.