I guess you want to use a device to recieve WISP signal and provide for the clients in the boat?
If I get the right request, I recommed you to use a CPE210.
It is compatible with 11b/g/n as you demand, but the scenario may be a little different that you can set it up on the deck and configure it on the WISP mode.
Then, wired connect it in the cabin to a wireless router WAN port and use the wireless router to provide indoor signal coverage.
It's not difficult to load 5 clients. But in order to improve the quality of wireless communication you have better not to connect too many device to the router at the same time.
Wish the information above can help you.

CPE210 doesn't support external antenna, TL-WA5210G can meet your requirements, you can attach your current antenna to TL-WA5210G via a type N to rp-SMA cable, it supports 11b&g while doesn't support 11n.
http://www.tp-link.com/en/products/details/cat-37_TL-WA5210G.html

Then choose AP Client Router mode which is same as the WISP mode which stupidbird mentioned above, and remember to choose external antenna under wireless menu...
Though TL-WA5210G is a very old product, its performance is not as good as new product such as CPE210, anyway, I think it can meet all your requirements

Thank you for your suggestions. I will look into it and try to get my mess reconfigured soon to be ready for next season. What I stumble over is the continued recommendations for Bullets. At $75 they are in what I call mid price range and Ubiquiti provides scant user help. I know that for a fact, after my numerous calls to them for help. Last season I had a problem getting another bullet working which I asked for help. I finally did get it up (later it bricked) and the tech I was working with asked me if I could tell him the steps I took so he could help others. Really now!

So with two bricked Bullets on the boat.......one of them an earlier failure that Ubiquiti replaced (bricked) under warranty..............I have no longer any use for their products. Important to point out that all my Bullets were operated under the cover of my boat's canvas, attached to a 15 db antenna also under canvas.

Why is there so much praise for Bullets????

Thanks again--

Foggy