And I don't mean specific to your boat. Just tools that are for boats.
The average boat would float a foot higher if the tools and spares were removed. What about boat-specific tools that you only grew to appreciate after a few years in the trenches? Here are a few of my favorites:
81. PelaOil Change Pump. I really should list this one twice, since most of the time I'm not using it for oil. In fact, I have two of these.
Pumping the bilge. Or rather all five of them. My F-24 has two sumps in each ama (outrigger) and a main sump, none or which have installed pumps or collect much water. The simplest solution has been a clean (don't change the oil with the same pump unless you want a fine for oil pollution) oil change pump. Just give it a few strokes, stick the hose in the sump, and a minute later you are done. No fiddling with hoses or power. If Ive been good, I can knock out all of the sumps in one fill, if I've been lazy, I might dump it once or twice, which takes only moments... if you keep it separate.
Changing the oil. You'll never grope for the plug again. Not only does it save time, it saves mess and pollution potential. Depending on the motor, you may want to add a semi-rigid extension wot the wand made from aluminum or copper tubing so that you can get to the very bottom. They pump a little faster if the oil is warm, but either way it will only take a few minutes, and they oil is in a nice container to transport it to the recycle center.
82. Hose Pick. For certain, you want to get one of these before tackling a sanitation hose removal project. Really, any hoses that need to come off barbs. Combined with a pair of rubber faced gloves for grip, these can generally break any hose loose with minimal effort and without damaging the barb. Use a hacksaw an you might as well resign yourself to replacing the barb as well, for it will surely leak. New hose clamps, of course.
83. Refrigerator water container. Actually, for me it is an antifreeze container. I've adapted all of my water systems (head, fresh, AC) with Ts and valves so that they can be filled without taking anything apart. The nozzle is just the right size for 1/2-inch ID hose to slide on (make certain it is not tapered and that it is a nice fit, though a clamp is probably needed). It has a valve. I set it above the system I want to winterize, open the valve on the container and switch the valves on the boat, and the system pump draws the antifreeze in. Winterizing is the easy work of an hour.
Comfort tip: tape 4-inch wide strips of foam exercise tile inside the leg loops of your harness. Much more comfortable if you are going to be up there for a while.
84. Mast Mate. Although there are many climbing systems, I like the simplicity of a ladder. It is faster, the working position is more comfortable and higher, and the cost per years is trivial; mine is 25 years old and looks like new.
85. Sail Maker's Palm. I'm really surprised at the number of boats that don't have one on-board. It's a sail boat!! Mostly, mine isn't used for sail repair. I use it for whipping lines, finishing splices or even sewwing splices, sewing projects from webbing or canvas, or repairing gear and clothing. Then there are the home uses, including repairing your favorite work coat or repairing the boarder on a rug. Invaluable. Hand sewing skill is basic seamanship as far as I'm concerned.
I really thought I would come up with a lot of boat specific tools, but in the end, most hings were multi-purpose. Perhaps I bought them with a boat project in mind, but they've since been used around the house too much to qualify. That is a good thing. In fact, all but the refrigerator bottles get used at home; I've used the MastMate for tree work.