Give a thought to your inventory this winter to keep you cruising next season, says Rachael Sprot as she takes you through the tools you need on a boat

How many 13mm spanners does a girl need in her tool box? Well, at least four it turns out.

We were a halfway across the Atlantic bound for St Lucia on our Clipper 60, Bluejay, when the flexi-coupling on the generator failed.

The crew consisted of me and a professional first mate and eight amateur sailors of mixed ability.

Engineering fell to me, and in this instance, I needed two 13mm spanners.

Lucky I set off with three then isn’t it?

The unfortunate thing about luck is that it runs out.



The ratchet end of these high quality spanners can be the difference between being able to undo something in a tight space and not.

excellent quality spanners, these come in a roll, which keeps everything neat and easy to find.

Buy now from Screw Fix

A woman making repairs to a yacht

Have more than one set of key tools you couldn’t do without. Credit: Rubicon 3

The first one had disappeared over the side early on in the voyage.

When the second one clattered into the bilge of doom I was left with my third and final spanner and the dreaded adjustable wrench – and so a 10-minute job became a half-day affair.

To add insult to injury I had two 14mm spanners in the wrap winking at me mischievously.

‘It’s all right for you,’ I muttered, ‘you’ve never done a day’s work in your life.’

Of all the things I worry about when setting off for the season, the inventory is one of the foremost in my mind.

Offshore cruising has a way of helping you recognise what’s important in life, salient spanner sizes included.

Replacing a worn kicker swivel block on an ocean passage - makes sure you have the right tools for the job before you set off

Replacing a worn kicker swivel block on an ocean passage. Credit: Rubicon 3

At Rubicon 3 our vessels carry everything from epi-pens to angle grinders yet somehow there’s always an item that you didn’t know you needed until it’s too late.

My initial attempts at setting up the fleet inventory were a bit like Supermarket Sweep: you end up with a trolley load of buy-one-get-one-free offers but no chopped tomatoes.

It has taken time to refine and improve it.

Slowly each item on board has been weighed against three criteria: how critical it is; how likely it is to fail; and how hard it is to come by.


Continues below…

Critical systems

The secret to cruising is that you can do without most things once you’re out there.

For many critical systems you can’t carry a spare anyway – like your standing rigging or your rudder.

But there are lots of things you wouldn’t leave without in the first place, and these are the things that you need to identify.

Sure you can cross the Channel without your loo if you have to, but you wouldn’t carry on and explore Brittany on a bucket and chuck it policy.

Don’t just think of your inventory in terms of what might go wrong at sea, think of what will stop you putting to sea in the first place.

A spare impeller and whole service kit side by side

The difference between carrying a spare impeller and a whole service kit. Credit: Rubicon 3

Identifying critical systems is easier said than done though.

The main engine is universally essential, but most yachts also rely heavily on electrics and electronics.

Domestic systems are often overlooked in the process of identifying critical spares.

Could you cope without your fridge, oven or running water for a week?

We now carry spare gas regulators (they always fail in a closed position – safe but annoying), fridge thermostats and a fresh water pump as their failure has a huge impact on life on board.

Preparing for gear failure

With our fleet of expedition yachts covering around 60,000 miles each year between them, we’ve learnt the hard way which systems are likely to fail.

They broadly fall into two categories: things that should or shouldn’t move; and things that should or shouldn’t be wet.

Things that should move

Anything which has moving parts can eventually wear out. Pumps and electric motors are two of the most common pieces of equipment to fail.

A seized electric motor isn’t serviceable at sea, so we carry spares and swap out the whole unit.

It can be expensive investing in spare water pumps, starter motors and alternators, but if you’re cruising remotely you’ll save money in the long run by not shipping parts around the world.

The rubber parts of diaphragm pumps will also degrade over time, becoming brittle.

Things that shouldn’t move

There are many things on board which aren’t designed to move, but that with time, corrosion and frequent loading and unloading become loose.

Deck hardware, spars and standing rigging are often susceptible to crevice or galvanic corrosion.

These items are expensive and difficult to replace so your best approach is to maintain them well, ensure that you have redundancy in the system and carry materials for jury-rigging.

Having a supply of soft shackles and a length of Dyneema will provide a short-term solution to many issues.

Chafe is always an issue. A spare halyard could be used for many different jobs.

Hoses and electrical cables in engine bays are often damaged too.

A cheap hose connector can be used to join damaged sections and lengths of electrical cable could get you out of trouble.

Things which should be wet

Any impeller-driven pump needs to run wet.

A blockage on the inlet will result in a shredded impeller, so spares are essential.

Wherever possible, we carry the full pump service kits.

These include paper gaskets, spare cover plate screws in case you drop one in the bilge and a seal kit, as well as the impeller.

Other things needing lubrication include windlasses, winch parts, the stern gland and rudder bearings.

You can’t always carry spares for these but regular servicing will identify parts which need replacing before they fail.

Things which should be dry

The biggest cause of electrical failure on a yacht is corrosion from the damp, salty environment.

There’s only so much we can do about this once we’re out there: the time when you notice your deck fittings are leaking usually isn’t the time to start re-bedding them.

You need  a good supply of cable terminals, waterproof grease and (dare I say it?) duct tape, so that you can stem a leak and make good any corroded connections until there’s an opportunity for a longer term fix.

Gas supply parts for a yacht

Domestic systems like the oven and gas supply are easily overlooked. Credit: Rubicon 3

It helps to follow this process when identifying critical spares:

Methodically consider each system on board.

Decide whether you would carry on cruising if it failed.

This is quite personal, and one person’s ‘essential’ will be someone else’s ‘luxury’.

Consult the manual for your critical systems, identify which parts could fail and which spares you want to carry.

Which tools & spares do you really need?

Sometimes it’s not economic or practical to carry spares.

If you’re selecting a yacht for long-distance cruising you need to look for redundancy in areas where you can’t carry spares: paper charts and a hand-held GPS in case your chartplotter fails; beefy chain plates and spare mast-head halyards to replace standing rigging; ways to charge your batteries should your engine fail.

Some items on board are almost impossible to source in the average chandlery.

The more expensive engine spares are one of them: alternators, starter motors, head gaskets.

A feamle sailor opening the door of an oven onboard a boat

Domestic systems for cooking and heating can be equally as important as mechanical systems. Credit: Rubicon 3

They may not be things you’d replace yourself, but they are things that a good mechanic could fit for you, as long as you can provide the parts.

It’s easy to forget the accessories which make up the whole job, focussing on the big-ticket items.

If you’re changing out an injector you also need to replace the copper washer which it sits on.

Wherever possible carry the spare part and its accompanying accessories like O-rings and gaskets.

Starter motors and alternators are a fairly common source of failure

Starter motors and alternators are a fairly common source of failure. Credit: Rubicon 3

It’s worth having a supply of emergency ‘bodge it’ items like plywood, Sikaflex, epoxy and fibreglass matting.

Underwater setting epoxy is particularly useful, for obvious reasons…

If you’re cruising remotely ask your local GRP specialist to put together an emergency pack for you.

The spares you carry need to reflect what’s available on shore.


In the Solent you can source most things within 24 hours; in Northern Europe, the Med and the Caribbean you’re never too far from a good chandlery, but it may be a few days away.

Once you venture further afield to the high latitudes, South America or the Pacific you need to be much more self-reliant.

To help you identify which spares you need, we’ve grouped them by three areas: coastal, where you have good facilities ashore; offshore, where you may be a few days away from support; and remote, where it might take weeks for parts to arrive.

A full range of spanners should be part of the essential tools onboard

Double up on important spanner sizes such as 8, 10, 13 and 17mm. Credit: Rubicon 3

The most important thing you carry isn’t your spares, however.

It’s your tool kit and your skillset – without them many of your spares will be useless.

Invest in the right training and equipment and it’ll save you time and money in the long run.

If there’s one thing I’ve learnt about the inventory though, it’s that it will never be complete.

Rachael Sprot

Rachael Sprot is a Yachtmaster ocean instructor and director of Rubicon 3, the offshore yacht sailing school

We can never carry everything we need for all the disasters we might face, but ingenuity and imagination will often provide what our stores cannot.

After all, the wisdom of the inventory is not knowing what we do need but removing what we don’t.

Anything superfluous makes the important stuff harder to find.

Sailing is an exercise in minimalism: consciously and unconsciously when we set off from land we’ve already made the edit.

There’s no room for sentimentality on board, we take with us what we need.

So start your tools and spares inventory by making a pile of what you don’t need and you’ll start to see what’s important.

I’m starting with those 14mm spanners.

Spares checklist


Engine & generator:

Fuel filters
Oil filters
Relays and fuses


Hose repair kit

Rigging and sail repair:

Needles and sailmakers palm
Waxed thread
Length of webbing
Adhesive sail repair patches


Selection of fuses
Cable terminals and crimpers
Cable ties
Navigation light bulbs
Cabin light bulbs

Dinghy and outboard:

Dinghy repair kit


Duct tape
Sand paper
White spirit or other thinners


Engine & generator:

Fuel lift pump
Length of spare fuel hose (for jury rigging into a jerry can)
Raw water pump service kit


Heads service kit
Bilge pump service kits
Hose connectors and jubilee clips for common hose sizes (1/2”, ¾”, 1”, 1 ½”)
Grey and black water pump/ macerator service kits
Push fit connectors and fittings if plumbed with rigid pipe


Gas regulator

Rigging and sail repair:

Mainsail sliders
Soft shackles
2-3m of Dyneema


Selection of wire in various sizes
Shore power plugs and connectors
Choc-block connectors
Fuses for all electrical equipment

Dinghy and outboard:

Spark plugs
Fuel filters


Marine grease
Rust penetrant spray
Anti-corrosion compound (Duralac)


Engine & generator:

Starter motor
Comprehensive gasket kit
Injectors and washers
Engine mounts


Spare fresh water pump
Spare Grey and Black water pumps
Length of hose for each essential system, normally: ½”; ¾”; 1”; 1 ½”
Selection of through hull fittings and ball valves


Cooker and hob valves and thermostats
Fridge and freezer thermostats
Heater glow plugs and filters

Rigging and sail repair:

Large piece of Dacron cloth
Halyard-length of line
Swivel and snatch blocks


Spare inverter
Coax cable connectors
Spare battery terminals
Length of battery cable, crimp connectors and large crimpers

Dinghy and outboard:

Water pump service kit
Oil filter
O-rings and gaskets for draining oil


Corrosion-guard spray
GRP repair kit

Tools checklist


Hand tools:

Spanners and adjustable wrenches
Basic socket set
Allen keys
Oil filter wrench
Hacksaw and blades
Stanley knife and blades
Tape measure

Electrical kit:

Side cutters

Power tools:

Drill and drill bits


Hand tools:

Small electrical screw drivers
Double up on key spanner sizes
Comprehensive socket set
Torx set
Mole grips
Rubber mallet

Electrical kit:

Amp clamp

Power tools:

Heat gun
Work lamp


Hand tools:

Taps, dyes and helicoil sets for common sizes
Extra large adjustable wrench
Wire brush selection
C Clamps & Vice
Vernier calipers

Electrical kit:

Soldering iron and flux

Power tools:

Angle grinder and cutting discs
Gas powered blow torch