Maintenance and Repairs on Board

Prerequisites

• RYA Competent Crew or equivalent, with a basic knowledge of the parts of a yacht, her rig and her sails.
• Day Skipper lessons on Safety Equipment and Engine Checks and Maintenance. The engine is covered there and is only referred to here.
• Comfort with simple hand tools: spanners, screwdrivers, pliers and a multimeter.

Learning Objectives

By the end of this lesson you will be able to (RYA Day Skipper practical syllabus: Preparation for sea, Boat handling and Engine and systems; shorebased syllabus: Safety and Passage planning):

• Carry out a structured check of the standing and running rigging before a passage (RYA syllabus: preparation for sea, rig checks).
• Inspect sails and make a temporary repair to stitching or a tear.
• Explain how a winch works and service one safely.
• Check, operate and maintain seacocks, and know what to do if one fails.
• Use and clear a marine toilet (heads) and maintain the bilge pumps.
• Understand a yacht's 12 V system, test batteries and find simple electrical faults.
• Apply a logical fault-finding method to any system on board.
• Assemble a sensible spares and tool kit for coastal cruising.

RYA Syllabus Map

What the examiner expects. A Day Skipper is responsible for the boat as well as the crew. On the practical course you may be asked to show the boat's seacocks, explain how to operate the heads and pumps, check the rig before departure and say what you would do if something failed at sea. You are not expected to be a marine engineer, but you should be methodical, safe and able to keep a simple fault from becoming an emergency.

Why Maintenance Matters to a Skipper

Most failures at sea start as small, visible problems: a split pin missing, a frayed sheet, a corroded terminal, a hose clip rusting through. Lifeboat call-out records show that machinery and equipment failures are among the most common reasons for small-craft rescues. Regular checks catch problems before they become emergencies, and a basic repair skill set lets a skipper get home safely when something breaks.

Three principles run through this lesson:

1. Check before you go. A pre-departure routine catches most problems in harbour, where they are easy to fix.
2. Keep it simple at sea. Make a safe, temporary repair and get to harbour. Leave full repairs for the dock.
3. Carry the right spares and know where they are. A spare is useless if nobody can find it.

On a chartered boat, report defects to the charter company and do not attempt major repairs yourself unless they agree. Keep a defects list in the log.

Checking the Rig

The mast is held up by the standing rigging; the sails are controlled by the running rigging. A rig failure can bring down the mast, injure crew and leave you without propulsion in bad weather.

Standing rigging

Before a passage, and at least at the start of each charter or season, walk the deck and check:

• Rigging screws (bottlescrews): locking nuts or split pins in place; no bent bodies; threads not over-extended.
• Clevis pins and split pins: every pin present and its split pin opened out, taped to prevent snagging sails.
• Chainplates: no movement, no cracks in deck sealant, no rust weeping (a sign of water ingress and corrosion).
• Wire: run a cloth along the lower part of each shroud and stay. A broken strand will snag. Look closely at the swaged terminals where the wire enters the fitting; cracks or rust here are a warning. Many insurers expect standing rigging to be replaced roughly every 10 to 15 years, depending on use.
• Forestay and furler: furling drum turns freely, the furling line is not chafed, and the top swivel is not wrapped (halyard wrap can break the forestay).
• Mast step and partners: no cracks, no compression of the deck.

Going aloft

A full rig check means someone going up the mast in a bosun's chair. At Day Skipper level, you should know the safety rules even if you send a rigger:

• Use a proper bosun's chair or climbing harness, on a halyard in good condition, with a second halyard as a safety line.
• Use a winch and a competent winch operator; never use a self-tailer without a hand on the tail.
• Nobody stands directly below; tools are tied on.
• Only in harbour and in calm conditions.
• Check spreader ends, the masthead sheaves, lights, aerial connections and wind instruments.

Running rigging

• Halyards, sheets and control lines: look for chafe, especially where lines run over sheaves, through clutches and at the shackle end.
• Shackles: pins tight and moused (secured with wire or a cable tie) where they could shake loose.
• Blocks and sheaves: turn freely, no cracks in the cheeks.
• Reefing lines: run freely, and the crew know how to use them.
• End-for-ending a sheet or halyard moves the worn section to a less loaded place and extends its life.

At sea

Get into the habit of a daily rig walk on passage. Listen for new noises and watch for movement. If a shroud parts, act immediately: tack or gybe to put the damaged side to leeward, so the remaining rigging takes the load, and reduce sail. Rig a spare halyard to the chainplate as a temporary shroud.

Sails

Inspection

Lay the sail out, or look closely as it is hoisted and furled:

• Stitching: UV light breaks down polyester thread, especially on the leech and foot of a furling headsail. Thread that rubs off easily with a fingernail is failing.
• UV strip: on a furling headsail, the sacrificial strip protects the sail when furled. If it is coming away, get it repaired.
• Chafe points: where the sail touches the spreaders, shrouds and pulpit. Spreader patches help.
• Corners: the head, tack and clew carry the highest loads. Look for elongated or pulled-out rings and webbing.
• Battens and pockets: battens secure, pockets not split.
• Slides and luff tape: slides intact; luff tape not worn where it enters the mast track.

Temporary repairs

A sail repair kit should include sticky-back sail repair tape, needles, waxed whipping twine, a sailmaker's palm, and a small knife. For a small tear:

1. Dry the sail and clean it with a little fresh water or alcohol wipe if salty, so the tape sticks.
2. Lay the sail flat on a hard surface.
3. Round the corners of the repair tape, so it does not peel.
4. Apply tape to both sides, overlapping the tear by at least 5 cm on every side.
5. For a larger tear or at a load point, add a line of hand stitching through the tape with the palm and needle, using a simple running or zigzag stitch with stitches 5 to 10 mm apart.

Reduce the load. Reef, or partly furl the headsail so the damaged area is rolled away. A temporary repair is to get you home, not to carry on racing.

Winches

Winches carry large loads. A seized winch is a nuisance; a slipping or failing pawl can injure someone.

How a winch works

The drum turns one way only. Inside, spring-loaded pawls engage a toothed ring so that the drum cannot turn backwards. Gears give two or more speeds depending on the direction you turn the handle. Pawls and springs are small, and a broken spring can let the drum slip back under load.

Servicing

Most manufacturers recommend servicing winches at least once a season, more often in heavy use.

1. Read the manufacturer's manual. Designs differ.
2. Place a towel or bucket around the winch to catch parts. Never service over open water without a catch.
3. Remove the top cap or retaining clip and lift the drum off carefully. Note the order of parts or take photos.
4. Remove bearings and gears and clean them with a degreaser or paraffin. Old grease and salt should come away.
5. Inspect pawls and springs. Replace springs that are weak or rusted (they are cheap; carry spares).
6. Grease the gears and bearings with winch grease, lightly.
7. Oil the pawls lightly with light machine oil, not grease. Greased pawls can stick open and fail to engage.
8. Reassemble, then check the drum turns freely one way and locks the other way.

Safety with winches. Keep fingers clear of the drum, take three or four turns before loading, and remove the winch handle when not in use.

Seacocks

Seacocks are valves on through-hull fittings for engine cooling water, heads, sinks and cockpit drains. A failed seacock or hose is one of the most common causes of flooding.

Know where they are

Every crew member should know the location of every seacock. Draw a simple plan and post it by the chart table. Label each one. On a typical 10 metre yacht there may be six to ten.

Checks

• Operate each seacock at least once a month, and before a passage. Seized valves cannot be closed in an emergency.
• Hose clips: two stainless clips on each below-waterline hose; look for rust on the screw threads.
• Hoses: no cracks, no softening.
• Material: through-hulls and seacocks should be bronze, DZR brass (dezincification resistant, often marked CR or DZR) or a suitable reinforced plastic. Ordinary brass can lose its zinc in seawater and become weak and pink in colour. Have suspect fittings checked when the boat is ashore.
• Bungs: a softwood tapered bung of the right size tied to each seacock, ready to hammer in if the fitting fails.

Policy at sea and in harbour

Many skippers close the heads seacocks when the boat is left or when sailing hard, to prevent back-siphoning. Close the engine intake when leaving the boat for long periods, but put a reminder on the engine start key so nobody starts the engine with it shut.

If a seacock or hose fails

1. Raise the alarm and get crew pumping.
2. Find the source. Taste the water: salty or fresh?
3. Close the seacock if possible.
4. If the fitting has broken, hammer in a softwood bung or use a proprietary stopper.
5. Keep pumping and monitor.

See the Fire, Flooding and Abandon Ship lesson for full flooding procedures.

Heads

Marine toilets cause more call-outs to charter companies than almost anything else. Brief every crew member at the start of the trip.

How it works

A manual heads has an inlet seacock for flushing water and an outlet seacock for waste. A lever selects "flush" or "dry". Waste goes either overboard or into a holding tank, depending on the boat and local rules.

Rules for crew

• Nothing goes in the heads that you have not eaten first, apart from a small amount of toilet paper.
• Pump enough strokes to clear the pipe completely, typically 10 to 15 full strokes, and then a few more to flush clean water through.
• Leave it in the "dry" position when finished, to avoid back-siphoning and flooding when heeled.
• Close the seacocks as instructed by the skipper.

Maintenance and blockages

• Scale: urine and seawater form a calcium scale in pipes. Pumping a little white vinegar through and leaving it overnight once a fortnight helps dissolve it.
• Lubrication: a little vegetable oil pumped through occasionally helps the seals.
• Blockages: check the seacocks are open first. Then check the joker valve (the rubber one-way valve at the outlet), which is often the cause. Changing it is an unpleasant but simple job; carry a spare and a service kit. Always close the seacocks before dismantling anything.

Bilge Pumps

Every yacht should have at least two bilge pumps: one manual pump operable from the cockpit, and one from below. Many also have an electric pump with a float switch.

Checks

• Test every pump before each passage. Pour water into the bilge and pump it out.
• Strum box: the strainer at the pump intake clogs with hair, sawdust and labels. Clean it.
• Handles: tied on near the pump, so nobody loses one overboard.
• Electric pump: lift the float switch by hand and check the pump runs. Check the fuse and the bilge alarm, if fitted.
• Keep the bilge clean: debris blocks pumps just when you need them.

Capacity

A manual diaphragm pump moves perhaps 30 to 60 litres per minute with steady pumping. A 25 mm hole 0.5 metres below the waterline lets in roughly 60 to 90 litres a minute, more than one crew member can keep up with; a 50 mm hole lets in four times that. Pumps buy time; stopping the leak is what saves the boat.

12 V Electrics and Batteries

Most yachts run on 12 volts DC from lead-acid batteries, charged by the engine alternator, shore power and sometimes solar or wind. Lithium batteries are increasingly common and need their own management system and charger settings.

Battery banks

Typically there are two banks: an engine start battery and a domestic (service) bank for lights, instruments and the fridge. A battery switch or splitter keeps the start battery for starting, so you can always start the engine even if the domestic bank is flat.

Checking state of charge

With a multimeter, measure the voltage of a lead-acid battery that has rested with no charge or load for a few hours:

Lead-acid batteries last longer if not discharged below about 50%. When the engine is charging, the voltage should rise to around 13.8 to 14.4 V. If it stays at 12.5 V or less with the engine running, the alternator is not charging: check the drive belt and connections.

Battery safety

• Batteries must be securely fixed so they cannot move in a knockdown.
• Charging lead-acid batteries can give off hydrogen. Keep the compartment ventilated and no naked flames nearby.
• Wear eye protection when working near batteries.
• Never short the terminals with a spanner: a battery can deliver hundreds of amps and cause burns or fire.
• Remove the negative terminal first and reconnect it last.

Power budget

Estimate your daily consumption in amp hours. For example: navigation lights 2 A for 10 hours = 20 Ah, instruments 1 A for 24 hours = 24 Ah, fridge 4 A for 12 hours = 48 Ah. Total roughly 90 Ah a day. A 200 Ah domestic bank used down to 50% gives about 100 Ah, so you need to recharge every day.

Fault Finding

A logical approach solves most problems. The same method works for electrics, pumps, heads and the engine.

1. Make it safe. Stop the system, isolate the power or close the seacock, and check the boat is in no immediate danger.
2. Define the fault. What exactly is not working? When did it start? Did anything else change?
3. Check the simple things first. Is it switched on? Is the breaker tripped or the fuse blown? Is the seacock open? Is the tank full?
4. Follow the system from source to load. For electrics: battery, main switch, breaker or fuse, wire, switch, device, and back via the negative. For water: tank or seacock, filter, pump, hose, outlet.
5. Test, do not guess. Use the multimeter to find where the voltage disappears. A reading of 12 V at the battery and 0 V at the device means the break is in between.
6. Change one thing at a time, and test after each change.
7. Decide whether you can repair it, can manage without it, or need help.

Common electrical faults

Never replace a fuse with a larger one. It is there to protect the wire from overheating.

Spares and Tool Kit

Tool kit

• Combination spanners and an adjustable spanner, metric and imperial if the boat needs both.
• Screwdrivers, flat and cross-head, including a stubby.
• Pliers, long-nose pliers, mole grips.
• Socket set.
• Allen keys.
• Multimeter.
• Hacksaw with spare blades, and a bolt cutter or rigging cutter capable of cutting the shrouds in a dismasting.
• Sharp knife.
• Hammer.
• Torch and headtorch.
• Electrical tape, self-amalgamating tape, duct tape and cable ties.
• Wire brush, emery paper, and water-repellent spray (such as a moisture displacing spray) for electrical contacts.

Spares

Keep the spares in labelled, waterproof boxes, list their location, and check the list at the start of each season.

Worked Example

You are skippering a chartered 11 metre yacht on a two-day coastal passage. During the morning handover check you find:

1. A split pin missing from the clevis pin at the foot of the starboard cap shroud.
2. The cockpit bilge pump handle missing.
3. The domestic battery reading 12.1 V after the boat has rested overnight on its mooring with the fridge running.
4. The heads lever stiff and the bowl slow to empty.

Actions.

1. Split pin. Fit a new split pin from the spares box, open it out and tape it. Check the other shrouds while you are there. This is a rig safety issue and must be fixed before sailing.
2. Pump handle. Look for it below, and phone the charter base. Without a working cockpit pump you lack a key piece of safety equipment. Do not sail until a replacement is found.
3. Battery. 12.1 V is roughly 35% charged. Plan engine charging time, turn the fridge off overnight, and check the alternator charges to around 14 V with the engine running. Calculate the power budget: if you will be under sail for 8 hours with instruments and plotter on, you need to recharge at the next port.
4. Heads. Check both seacocks are open. Pump some fresh water and vinegar through. If it is still slow, the joker valve may be blocked or scaled; report it to the base and use the marina toilets until fixed.

Log entry. Record each defect, the action taken and the time, and tell the crew about any restrictions.

Common Mistakes

• Skipping the pre-departure check because the boat "looked fine yesterday".
• Greasing winch pawls, so they stick and fail to engage.
• Leaving heads seacocks open when sailing hard on a boat prone to back-siphoning.
• Seacocks never operated, then seized solid when needed.
• No bungs, or bungs stowed somewhere else in the boat.
• Fitting a larger fuse to stop a fuse blowing.
• Running the domestic bank flat and finding the start battery flat too because the switch was left on "both".
• Attempting a full repair at sea when a temporary fix would get you home.
• Not briefing crew on the heads, leading to a blockage on day one.

Summary

A Day Skipper is responsible for the boat. Check the rig, sails, winches, seacocks, heads, pumps and electrics before every passage, and keep a defects list. Operate seacocks regularly and keep bungs beside them. Brief the crew on the heads. Service winches by oiling pawls and greasing gears. Know the resting voltage of a healthy battery and check the alternator is charging. When something fails, make it safe, check the simple things, and follow the system from source to load one step at a time. Carry a sensible tool kit and spares, and know where they are. For the engine, see Engine Checks and Maintenance.

Check Your Understanding

1. List four checks you would make on the standing rigging before a passage.

Answer: Split pins and clevis pins in place and opened out; rigging screws locked; chainplates secure with no cracks or rust weeping; wire free of broken strands, especially near swaged terminals; furler turning freely with no halyard wrap.

1. Why should winch pawls be oiled and not greased?

Answer: Grease can make the pawls stick in the open position, so they fail to engage the ratchet and the drum can run back under load.

1. A domestic battery reads 12.2 V at rest. What is its approximate state of charge, and what should you do?

Answer: About 50%. Recharge it before discharging further, by running the engine or connecting to shore power, and review the power budget.

1. What should be attached to, or stowed next to, every seacock?

Answer: A softwood tapered bung of the right size, ready to hammer into the fitting if it fails.

1. The heads will not pump out. What would you check first?

Answer: That the inlet and outlet seacocks are open and the lever is in the right position. Then suspect a blocked or scaled joker valve. Close the seacocks before dismantling anything.

1. Describe the general fault-finding method.

Answer: Make it safe; define the fault; check simple things first (switches, fuses, seacocks); follow the system from source to load; test with a meter rather than guessing; change one thing at a time; decide whether to repair, manage without or get help.

1. Why must a blown fuse never be replaced with a higher-rated one?

Answer: The fuse protects the wire. A larger fuse lets too much current flow, the wire can overheat, and a fire may start.

1. How would you make a temporary repair to a small tear in a sail?

Answer: Dry and clean the area, lay the sail flat, apply rounded patches of sail repair tape to both sides overlapping the tear by at least 5 cm, add hand stitching for a larger tear or load point, and reduce the load by reefing or furling.

Further Reading

• Engine Checks and Maintenance: daily checks, impeller, filters and bleeding the fuel system.
• Safety Equipment: bilge pumps, bungs and flooding kit.
• Fire, Flooding and Abandon Ship: dealing with flooding and electrical fires.
• Vessel Systems Maintenance: deeper coverage of systems for longer passages.
• Manufacturers' service manuals for your winches, heads and pumps.