I know a bunch of years ago before I retired, one of my direct reports and her hubby were "coasties" (as they called themselves) and were still in the reserves at the time. One of my trips to her office eventually netted me a weekend where I got chance to go on her and her hubby's 30 fter and their sea-doos, which were docked in an IN tributary to the OH River and we ended up traveling along the tributary out to the OH and sea-dooing there with the barges! 
I learned a lot about the "rules of the road (water) ", which was fascinating (like shifting to idle when passing under a bridge, etc).
One of my BILs was in the navy and one of my great-uncles (who I never met) was in the Merchant Marines (which is probably why I never met him since he was out to sea all the time 
). Another aunt's hubby's family had a houseboat docked in Lake Champlain that we visited years and years ago and one of my cousins actually lived on one down in the Baltimore area for a bunch of years.
I just say hats off to any mariners out there and there are a number who are DUers. It's a whole other world (and I expect, a great hobby to boot). 
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