We have been asked to provide a list of tools required for boat maintenance. This is another virtually impossible task because of the variations in age and equipment fitted to boats, but here is some guidance for the engineering side of things.
Spanners (including socket spanners) come in four main size "families". To be sure of having an exactly correct spanner you would need one large set from each range, but the guide below should help you sort out what you actually need. There is a problem with the change over points because old designs tend to use the older sizing for longer.
Providing it is a good fit there is no harm in using the "wrong" series of spanners on your nuts and bolts, but YOU MUST NOT TRY AND MIX THE NUTS AND BOLTS the threads are different, and if you force them together you will damage (strip) them.
I would suggest combination spanners (a single spanner with a ring spanner on one end and the same sized open ended spanner on the other) and sockets if you are buying new, otherwise anything which gives you two ways of holding the same sized nuts & bolts.
All Modern Equipment
Expect anything originally made in the last 10 years to use METRIC sizes. Also most continental or Japanese equipment up to about 25 years old.
These tools are marked with numbers the one marked 13 having a gap of about ½" between its jaws. Try and get a set running between about 8 and 22 mm (although a lot will run between 10 and 17mm these will do to start, but be prepared to visit you local car shop if you find you need more).
UK built equipment between mid 1950s and mid to late 70s and all American equipment until late 80s
These are likely to use AF sized nuts and bolts. The markings will be a simple fraction e.g. ½ or ¾ . Some very small sizes might also have a number followed by AF e.g. 10 AF.
The sizes you need are 3/8 to about 1" AF, again a smaller range will be OK. Try and get these second hand.
Pre mid 50s British equipment and most plumbing fittings.
These require Whitworth/BSF (same size, but BSF uses a smaller fraction) sizes. They are marked in fractions and unless very old the fractions will be followed by "BSF" or "W" or "WHIT". Only get these if you find equipment that uses them car boot sales are your best bet.
A ½" x 9/16" open ended spanner is usefull for plumbing fittings.
BA Sized spanners
Until recently most "small" nuts especially on electrical equipment used BA sizing. These are very small spanners and run between 0 the largest, down to about 6. A set often consists of 0, 2, 4, and 6 BA.
As long as my vehicle students do not find out I said this, I would suggest you ignore BA spanners and resort to a small adjustable spanner or pliers if you find you need them.
Socket sets are sized by the size of square that is used to fit them to the drives and handles and the "thread type" (AF or Metric)
Having found the sizing type you need (AF or Metric probably) I would advise a set which gives you the smallest sizes in ¼" drive and the larger ones in 3/8" drive. For really stubborn nuts you might need ½" drive. The sockets are turned with a variety of "handles". NEVER USE A RACHET HANDLE ON TIGHT NUTS & BOLTS, use a T bar or Knuckle bar (a bar with a half swivel on the end you fit the socket.
You might need a few "extra deep" sockets for special jobs. Only buy them if you need them.
Until about 5 years ago I would have advised you to get a reasonable screwdriver set with at least three screwdrivers each from the straight and POSIDRIVE series. Technically you also need three from the PHILLIPS series. These are more "pointy" and experience shows that Posidrive works well enough with Phillips screws, but a Phillips screwdriver in a posidrive screw damages both itself and the screw.
Now you also have to consider all the "tamper proof" heads used on equipment. I would suggest you get one of the "screwdriver plus 100 tip" type tools for special jobs, and the three straight point and posidrive screwdrivers. Add a pair of "stubby" drivers for difficult places and keep a look out for a right angled screwdriver (just a bent bit of steel) at a good price.
SOCKET HEADED SCREWS
These are any type of screw or bolt with a hexagon "hole" bored into the head. Again to be sure of a good fit you need one Imperial set (AF) and one Metric.
Inspect your boat and see if you have any (often on "clamp on" shaft couplings or centre of alternator shaft). Try and borrow a set to see which type is needed.
Do not buy the cheapest set because the corners will turn off. You may come across a much larger socket head. Rather than trying to buy a special key for it, think about bribing a local welder to weld a bolt with suitable sized head to fit the socket to a piece of scrap steel.
PLIERS AND GRIPS
"Ordinary" pliers are usually "Combination pliers" because their jaws are formed in a way to allow the gripping of round items and wire cutting.
I would suggest you get one large pair and a small pair for delicate work.
You will find a pair of "pin" or "long" nose pliers useful as well as a pair of SIDE CUTTERS for wire cutting and stripping.
A large "MOLE" or self grip wrench is useful, but not essential at first.
You will find a special sort of pliers called a GLAND NUT or WATER PUMP pliers very useful, especially on plumbing jobs. If your stern gland uses a big nut you need two pairs. One as big as you can afford (for the stern gland) and a smaller pair of about 8" to 10" length for general use. Again save up to buy reputable makes they do break/slip and crush your fingers.
These are only of use if you intend to start setting valve clearances or gearbox/injector rack set-ups that require their use. Do not attempt anything like this without a manual, and the manual will tell you if you need metric of imperial gauges. It will be written on the case, but the metric feelers will have a decimal point marked on them, .08 .38, whilst imperial ones will just have numbers.
If you do buy feeler gauges get a small, strong, plastic bag to keep them in and oil them before putting them away they go rusty very easily.
Many make do with the mooring lump hammer, but I would also buy a cheap steel-shafted carpenters (claw) hammer from a DIY shop. The claw end can be used as a lever.
A plastic faced hammer is nice if you intend to whack things you do not want to mark, but it is not essential as you can often cushion the hammer blows with a piece of wood.
SUNDRY USEFUL TOOLS
Small and large, good quality adjustable spanners.
Large and small "snap off blade" knives and spare blades. (Cheaper than a Stanley Knife ).
Terminal crimping kit for EMERGENCY USE ONLY. Consisting of assorted terminals and the crimping pliers.
Punch/cold chisel set.
Roll of plastic insulating tape.
Your own "special tools" these are ordinary tools modified by bending\cutting\filing to do a special job on your boat.
THE ENGINEERS BOX
You will find all the "old hands" have a secret store somewhere it needs to be secret because others will describe it as "that pile of junk". This will consist of "left over" items, old items which still have useful life left in them and a few new items.
This is what gets you out of trouble when you are miles from help. Some typical contents would be:-
Spare bulbs/ tubes
Assorted lengths of electrical cable.
Assorted split pins
Assorted hose clips
Assorted nuts and bolts (Packaged by thread type if you are organised but usually just lying in the bottom).
Assorted bits of hose.
Assorted electrical terminals
Choc. block connectors (3 Sizes)
Wood screws and self-tapping screws
Sundry plumbing fittings
More insulating tape
Self-amalgamating (hose repair) tape.
Special underwater setting repair putty.
Last years jabsco pump impeller
Last years fan belt(s).
Tube of car body repair paste (P38 for example)
Epoxide or polyester resin + hardener + filler.
Tub of Molygrease (Grease rich in molyslip)
Pieces of wood
Gasket paper (I use a piece of cereal packet and gloss paint in an emergency)
Jointing compound Nowadays Silicone sealer is a good.
Imagination shows you how to use what you have to get out of trouble
A Really good box takes years to build up, so the earlier you start the better it will be.