I've mostly been just skimming this thread because I use nautical terms out of habit since I was a kid around Mystic and there's no debate or need for justification in my mind, but it seems to me there are at least a couple of very clear reasons to use nautical terms. There's the functional or practical *utility* of nautical terms -- like so many have pointed out with port and starboard -- but then there's also a ton of vocabulary where regular household or residential substitutes just don't work, they're simply not descriptive. My house has walls, the boat has bulkheads. If I called the bulkheads walls, how does anybody know the difference between the hull and the interior "walls?" (I know, somebody raised that one already.) Other than the fact you look through both of them, the portlights on the boat are almost nothing like the windows in my house. The aft deck -- what would I call that area if I didn't call it an aft deck? (Or poop deck, or fantail, or whatever, as we beat to death in a recent thread.) What would I call the anchor windlass, the anchor chain twirly thing? The anchor windey thing? The anchor sucker-upper. What would I call the dinghy, the "little-boat-that-trails-behind-that-we-use-to-get-to-shore?" I could go on but you get the idea.
And then I also think that if this were a sailing forum rather than power (former sailors notwitstanding), we wouldn't even be having this discussion. How do we more efficiently or simply describe the difference between standing rigging and running rigging? Describe a "shroud" in one alternative, non-nautical word. Or any of the sails -- spinnaker = that balloon-lookin' sail in front? Or any sailboat type or configuration -- yawl, ketch, sloop, schooner. Or the phrases used to describe points of sail. Helm = "area with the steering wheel?" Well, unless it has a tiller. Wait, can't use tiller. The galley on the boat is very different than our kitchen at home, and perish the thought of my installing electric macerators in our home "bathrooms." Anybody who thinks we ought to ditch nautical terms, I'd like to see a glossary of the modern substitutes.
Rudder = big flat underwater flap that swings back and forth to change the boat's direction.
Keel = yeah, I have no idea. Bottom edge that runs fore to aft? Oops, can't use fore or aft.
Sponson = what, flotation-outrigger-attached-directly-to-the-hull?
Capstan = round cranking thingie. I guess a furling jib is a sail that sucks itself back in around the -- wait, can't use forestay...