Go for it. It is a nice shotgun. It is absolutely necessary to get a Marine type shotgun for use on a boat (especially in salt water).
I guess the other two choices are the Mossberg 500 Marine and the Winchester Model 1300 Marine Magnum. The Mossberg has the Ghost ring sites (if you get it that way) which are better than the bead sites on the Winchester, but I like the look of the Winchester better because it has a shiny nickel type finish. The Mossberg has a rougher satin golden finish. Pachmayr also has a great pistol grip (if you want a pistol grip) for the Winchester, which is better than the pistol grips for the Remington or the Mossberg (IMO). The Winnie is the lightest (If my memory serves me) so you will feel the recoil more with the Winnie.
Remington is probably best all around (function), but I don't know if it is worth the extra cash as compared to either the Mossberg or the Winnie. If it is on the boat, it ain't gonna see all that much use (probably) so you must do your own cost benefit analysis.
For the record I bought the Winnie after comparing all three. It was $105 bucks cheaper then the Rem, $25 bucks more than the Mossberg, and I just thought it was the coolest looking (superficial, I know, but what can I say?).