On my survey a few yrs ago, the Surveyor's Recommendations included putting in a Smart Plug. Since the insurance co wanted the SRs followed, they contributed $150 to the cost of the refit of my power cord. I bought the SP for about $180, did the swap myself, so got a much better plug to boat connection for about $30. (really cheap in $US).
Thread creep warning
Close the seacock? Whatever for? My engine water seacocks are not very accessible, but can be seen and after 36 yrs the Stb one still looks good. I changed out the Pt one 2 yrs ago because I didn't like the rusty handle, and could no longer move it. If I couldn't inspect, I might close them, but since I can see them, and am not ever going to mistakenly stand on them, due to their inaccessibility I don't worry about them failing. Also, I have never had any morine organisms take up residence beyond the seacock. I once had an oyster grow to cutting off the flow in my salt water pump intake screen, but that could be seen and cleared from the outside.
I like to be able to get under way without a long list of SOPs. I turn off AC power, check the gear shifter positions, and turn the key. while the engines are warming up a tiny bit, the power cord comes in and the lines come off. Usually under way before my dock neighbours can show up with a helping hand. I prefer that, as helping hands usually slow the process down quite a bit. Checking the oil and water is for after a run.
A friend has a cover over his throttles with a brief check list stamped into its metal.
1 item "make sure wife is aboard".