Every boat needs enough tools to deal with basic problems. The trick, especially on small and mid-sized boats, is carrying what you need for onboard repairs, yet not dragging along the equivalent of a Snap-On tool container. Here’s what I usually carry and why.
Dacron sail repair tape to mend upwind sails, holes in the boat, or even areas of chafe. If the boat’s sails use exotic materials such as carbon or Kevlar, I substitute sticky back Kevlar.
Nylon sail tape, which is used for nearly any spinnaker repair.
Ibuprofen helps with any pain, including crew who may have consumed to many alcoholic beverages the evening before.
Water additives such as Pedialite powder packs helps with hydration and energy. Keeps the crew fast and mentally sharp all day. Scissors to cut sail tape, rope, etc. Not necessary if the multitool has a good pair of scissors.
Magic marker to mark settings, halyards, etc. I write my name on my water bottle as well.
Lighter to burn ends of line and bungi to prevent fraying.
Sunscreen to prevent getting fried.
Two multitools. With two, you can hold a bolt from one side and the nut from the other to tighten rudder bolts, etc.
Bungee cord to replace broken or worn out bungee cords.
ChapStick, which other than the obvious, can be used to coat telltales, preventing them from sticking.
Small pins with rings. Ring-dings can get snagged on moving lines and pull out. And pins pop out. With a spare or two of the boats common sizes, I can easily replace them.
Electrical tape—for everything. Tape pins, mark lines, etc.
Telltales. We always seem to need telltales on shrouds or to replace them as they’ve fallen off sails. I stay ahead of the game by having some ready to go, along with small sticky back circles.
Batten key. Many boat’s sails use them to adjust batten tension, and they seem to go missing all the time. I always keep a spare squirrelled away.
Dyneema. A couple pieces of this can save the day—lash blocks, save broken outhauls, vangs, etc.