A survey report records a boat's condition on the day. But most boats are damaged not by defects but by habits. What follows is not from a rule book but from the water: situations met again and again, in command and in survey, and what they cost to prevent.
The common thread: almost every item here is prevented by a few minutes and a few hundred lira before it happens. Afterwards it costs ten to a hundred times that.
1. Mooring and Rope
A mooring line is not a sheet. This is the most common and most expensive mistake in a marina.
- Use three-strand nylon. A mooring line absorbs load by stretching. Braided polyester sheet rope does not; swell and wind load go straight into the cleat and the deck. The usual result: a cleat torn out, deck laminate cracked.
- Diameter: a rough rule is 1 mm for every 3 m of boat length. A 12 m boat takes 14-16 mm. Too thin parts; too thick will not stretch.
- Chafe point: a line wears where it passes the fairlead. Leather or hose protection costs a few hundred lira; a parted line costs the boat.
- Springs are what stop the boat surging fore and aft. Bow and stern lines alone are not enough.
- Length: leave slack for tide and wind pressure; a boat moored bar-tight has nowhere to give and works its hardware.
- Turn them yearly. Reversing a line end for end moves the wear point and doubles its life.
2. Anchoring
- Choose your neighbours. Anchor beside boats near your own length and type. A 12 m yacht and a 20 m motor yacht swing differently in wind and current; night wind shifts turn that difference into contact.
- Scope: on all-chain rode, at least five times the depth in good weather and seven to ten in bad; add the height of the bow roller above the water to the depth. Rope rode needs more. Short scope holds until the wind veers.
- Back down after setting. 1200-1500 rpm for 20-30 seconds. Confirm the set by lining up two fixed marks ashore.
- Use a snubber. A nylon line on the chain takes the load off the windlass. A windlass is a lifting machine, not a mooring fitting.
- Set an anchor alarm. A simple phone app tells you when you are dragging at night.
- Read the bottom. Mud and sand hold; rock and seagrass (posidonia) do not, and posidonia is protected.
3. Before a Blow: Thirty Minutes' Work
| Do this | Why |
|---|---|
| Close the sprayhood and bimini | Canvas left standing acts as a sail; it tears itself and pulls out the frame and the deck it is bolted to. This is the commonest post-storm damage. |
| Secure the furling headsail | An extra turn on the furling line, then lock it. A genoa that unrolls shreds in minutes and loads the rig. |
| Clear the deck | Cans, chairs, lamps, cockpit cushions, anything that flies is lost and damages the boat next door. |
| Double the lines | A second line in every direction; if one parts the other holds. Add chafe protection at the wear points. |
| Check fenders | Number and height; a fender hanging too low does nothing. |
| Try the bilge pump | Rain finds its way below; you want to know the pump runs before, not after. |
| Check battery charge | If shore power fails, the automatic bilge pump runs off the battery. |
| Close the seacocks | Heads, sinks and air conditioning left closed when you leave. |
4. Electrics and Fire
- Disconnect shore power if you are away for a while. A boat left plugged in corrodes faster galvanically; without an isolation transformer this is unavoidable.
- Unwind extension leads fully. A coiled reel heats. Reel fires are a known cause of marina fires.
- If you have converted to lithium, make sure charger, alternator and protection suit the chemistry, detail here.
- Keep extinguishers reachable. One at the back of a locker does not count. Check the gauge yearly, refill every five years.
- An engine room fire port lets you discharge without opening the hatch. Opening it feeds the fire.
5. Flooding and Seacocks
- A wooden plug beside every seacock, sized to the fitting and tied on. When a hose bursts there is no time to look.
- Double clips. Two stainless clips on every hose below the waterline, ABYC H-27 and one of the first things a surveyor checks.
- Exercise the valves. Open and close them monthly so they do not seize. A seized valve will not close when you need it.
- The bilge pump is not the whole defence. If capacity exceeds the ingress you buy time; if not, call for help immediately, see onboard emergencies.
- Touch the stern gland after a passage. Hot means it is out of adjustment; warm is normal.
6. Engine Habits
- Do not load a cold engine. Five minutes at idle first. Loading cold accelerates bore wear.
- Constant low revs are harmful. A diesel run long at low load builds soot.
- Check the raw water strainer before every trip. A bag or weed overheats the engine within a minute.
- Belt tension: about 10 mm of deflection under a thumb. A slack belt neither charges nor circulates properly.
- Leave the fuel tank full. A half tank in winter means condensation, where microbial growth in diesel begins.
- No water at the exhaust: stop at once. The impeller goes in thirty seconds, the exhaust hose melts within two minutes.
7. Rig and Sails
- Look and feel, monthly: cracks at terminals, broken strands, stiffness in the furler. A rig survey does this with measurement.
- Failure starts at the terminal. Wire rigging lasts 10-12 years; most failures are at the swage, not mid-wire.
- Split pins and tape: every clevis pin taped; an untaped pin works loose.
- Keep sails out of the sun. UV is sailcloth's first enemy; on a furler the sacrificial strip is checked.
- Halyards: lead unused halyards away from the mast, slapping is both noise and wear.
8. Laying Up
- Leave ventilation open. A sealed boat grows mould. Air must move under the cover, it shows in the joinery and upholstery.
- Keep the cover off the hull. Chafing cover abrades gelcoat and traps water.
- Drain the water system where freezing is possible: tank, pump and pipe runs.
- Batteries: either removed and stored charged, or on a smart charger. A lead-acid bank left flat sulphates.
- Deck drains: blocked scuppers pond water, which loads the deck and cracks it if it freezes.
- See the winterisation guide.
9. Insurance and Paperwork Habits
- Read the cruising area. Going outside it suspends cover in practice. Get written confirmation before moving to another region.
- Keep a photo archive. Photograph the boat systematically at the start and end of each season. It ends the "was that there before?" argument.
- Keep invoices. Every job done is evidence, in a claim and at sale. Undocumented maintenance counts as not done.
- Read the berthing contract, particularly lien and liability: berthing contract.
10. Guests and Crew
- A short brief: where the lifejackets are, where the extinguisher is, how the radio works, who takes the helm. Five minutes.
- One rule: one hand for the boat when moving on deck. Most people over the side go in calm weather, not a gale.
- Harness at night. Alone on watch, a jackline and harness are not a matter of opinion.
- Fuel and water: a third out, a third back, a third in reserve.
11. Comfort: Small Things
- Fender socks keep the topsides clean; bare fenders stick to gelcoat in summer heat.
- An awning is cheaper than air conditioning and drops cabin temperature noticeably.
- A small dehumidifier in a closed locker removes the musty smell entirely.
- Quiet: leading halyards off the mast is the best neighbourly act in a marina.
- A spare key with someone you trust: more boats end up locked with no way in than you would think.
12. Why This Page Exists
A survey measures condition. On a well-kept boat there is less to measure. Most of the above is the preventable form of what turns up as findings.
To see where your boat stands now, look at a condition survey; to move it elsewhere, skippered delivery.
Frequently Asked Questions
A mooring line is three-strand nylon and absorbs load by stretching. A sheet is braided polyester and is not designed to stretch. Used for mooring, it puts swell and wind load straight into the cleat and the deck laminate.
A rough rule: 1 mm for every 3 m of length. A 12 m boat takes 14-16 mm. Too thin parts; too thick loses the ability to stretch.
On all-chain rode, at least five times the depth in good weather and seven to ten in bad, with the bow roller height added to the depth. After setting, back down at 1200-1500 rpm for 20-30 seconds and confirm by lining up two fixed marks ashore.
Boats of different length and type swing differently in wind and current. A yacht and a motor yacht side by side can come together when the wind veers.
Closing the sprayhood and bimini. Canvas left standing acts as a sail; it tears and pulls out its frame and the deck it is bolted to. Then secure the furling headsail and clear the deck.
A boat left plugged in for long periods corrodes faster galvanically. Without an isolation transformer, disconnecting when you leave is the safer habit.
When a hose bursts there is no time to search. A tapered wooden plug sized to the fitting should be tied beside each valve. Every hose below the waterline also carries two stainless clips.
A diesel run long at low load builds soot. A few minutes at higher revs at the end of a passage clears it, if sea and traffic allow. From cold, idle for the first five minutes.
Yes. A half tank condenses on the inner surface, and that water is where microbial growth in diesel starts.
A systematic set of photographs at the start and end of each season ends the "was that there before?" argument and is among the strongest evidence in a claim.
Related Pages
Gas Systems (LPG)Shut-down order and ventilationOnboard EmergenciesFlooding, fire, engine failureWinterisation GuideAshore and afloatRig SurveyTension and terminal checksMarina Berthing ContractLien and liabilityYacht InsuranceCruising area and coverRepair GuideFrom finding to jobCommon Boat DefectsWhat comes up most oftenSurvey QuoteCondition survey pricing
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