You have the report and the findings are listed. Now the real question starts: what does this mean, how is it properly repaired, and what happens if it is done wrong? This page answers those three for the 100 findings that appear most often.
Why we write this: we do not sell repair work. Because we never sell repairs on a boat we have surveyed, there is nothing behind our saying "this is how the job should be done". The single purpose of this page is to turn your report into a scope document you can ask for quotations against.
From the field
Classifying a defect is harder than finding it. The same crack is cosmetic on one boat and structural on another, what decides it is where it sits and whether the load path runs through it.
That is why every finding carries its location and measurement. The class follows the load, not the photograph.
1. First: What Does the Finding Class Say?
| Class | Meaning | When |
|---|---|---|
| A | Affects safety directly | Rectify before the boat goes to sea. Not a negotiating point, a precondition. |
| B | Needed soon | Within this season. This is where negotiation actually happens. |
| C | Planned maintenance | Goes into the normal maintenance calendar. |
- ASafetyRectify before going to sea. Not a negotiating point.
- BThis seasonNeeded within this season. Where negotiation happens.
- CPlannedOrdinary maintenance calendar. Not for negotiation.
2. 100 Findings, Their Correct Repair and the Usual Mistake
3. Hull and bottom
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Osmotic blistering | Acidic fluid collecting under the gelcoat | Peel → wash → dry for weeks (confirmed by meter) → epoxy filling → barrier coat | Cutting the drying short; it returns within two seasons |
| Delamination (hollow sounding) | Laminate plies separating | Open the area, remove wet laminate, rebuild with compatible resin | Filling over the top |
| Wet sandwich core | Balsa or foam core has taken water | Cut the outer skin, replace the core, re-laminate | Only sealing the holes; the water stays inside |
| Grounding damage | Structural effect at and around the keel root | Define the extent by measurement, repair laminate, check bolts | Filling and painting the crack |
| Impact mark below the waterline | Local laminate crushing | Open, measure, rebuild ply by ply | Fairing the surface and moving on |
4. Gelcoat and paint
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Spider crazing | Gelcoat ageing, usually cosmetic | Sand and refinish gelcoat, or paint | Mistaking it for structural cracking and doing unnecessary work |
| Star crack | Point of impact | Check the laminate beneath first, then the surface | Covering the surface only |
| Antifouling build-up | Years of coats over coats | Full strip back, new primer system | Adding another coat on top |
| Incompatible paint / lifting | Different systems layered | Remove the system entirely and go to one system | Patching and carrying on |
| Fading and oxidation | UV exposure | Compound and polish; in advanced cases refinish gelcoat | Compounding until the gelcoat thins |
5. Keel and rudder
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Loose or corroded keel bolts | Rust weeping in the bilge, cracking at the root | Remove and measure bolts, renew where needed, torque to spec | Just tightening them; a corroded bolt snaps |
| Smile crack at the keel root | Movement or grounding | Open, repair laminate, check the bolt system | Filling it over |
| Water inside the rudder blade | Water has entered the blade | Open the blade, dry it, renew internal filling and laminate | Sealing the hole and leaving it; winter freezing splits the blade |
| Play in the rudder stock | Bearing wear | Renew bearings, measure the stock, renew the seal | Replacing the bearing without measuring the stock |
| Play in the steering system | Slack in cable or hydraulic transmission | Renew cable or hydraulic circuit, bleed properly | Treating the slack as normal |
6. Shaft and propeller
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Shaft misalignment | Vibration rising with revolutions | Realign on the engine mounts, measure the coupling | Tightening the mounts and carrying on |
| Cutless bearing wear | Radial play at the shaft | Renew the bearing; measure the shaft | Renewing the bearing without checking shaft straightness |
| Shaft seal leaking | Dripping at rest | Repack or adjust a traditional gland; renew the seal on a dripless type | Over-tightening and causing heat |
| Propeller damage or imbalance | Bent blade, knocking | Balance and straighten at a workshop | Hammering a blade straight in place |
| Shaft corrosion and stray current | Anode balance disturbed | Recalculate the anode plan, check the bonding circuit | Only adding anodes without finding the cause |
7. Rig and sails
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Crack indication at a terminal | Fatigue beginning, class A | Renew wire and terminals as a matched set | Changing one wire and leaving the rest |
| Swage corrosion | Salt and rust inside the terminal | Renew the terminal | Oiling it and carrying on |
| Chainplate leak | Deck bedding has aged | Remove, oversize the hole, fill with epoxy, re-drill and re-bed | Running silicone over the top |
| Corrosion at the mast step | Galvanic action on an alloy mast | Unstep the mast, cut and renew the base or correct the step | Painting over it |
| Furler binding | Bearing and seal wear | Strip down and renew bearings | Greasing and carrying on |
| Sail wear and seam failure | UV and fatigue | Restitch seams, renew UV strip; replace the sail when advanced | Patching through a season |
8. Deck gear
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Windlass failure | Motor, gearbox or control | Strip down, check motor and gearbox, renew seals and bearings | Replacing only the switch |
| Winch wear | Neglect and salt | Strip, clean, grease, renew pawls and springs | Never servicing them at all |
| Stanchion base leak | Water through the bolt holes | Remove, make an epoxy collar, re-bed | Sealing with silicone |
| Track and block attachments | Movement under load | Re-bed and re-bolt, add a backing plate where needed | Only tightening the bolt |
| Worn teak deck | Thickness lost, screw plugs showing | Renew the deck; the bonding system must be correctly specified | Laying new teak over old adhesive |
9. Hatches and ports
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Hatch leak | Seal and bedding aged | Remove, clean out all old bedding, re-bed with a compatible sealant | Running silicone over the top, the leak simply moves |
| Cracked or yellowed port | Acrylic ageing | Replace the pane; compatible material, stress-free fitting | Over-tightening and cracking the acrylic |
| Frame corrosion | Galvanic action on an alloy frame | Remove the frame, clean or renew it, fit an isolating gasket | Forcing screws and distorting the frame |
| Hull-to-deck joint leak | Joint sealant fatigued | Open the joint, clean it, re-seal and re-bolt | Sealing from the inside |
10. Electrical
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Undersized cable | Heating, voltage drop | Recalculate the load and fit correct section; match protection | Changing the cable but leaving the fuse |
| Missing circuit protection | Unprotected circuits | Correct protection on each circuit; a main isolator | Wire in place of a fuse |
| Broken bonding | Weak galvanic protection | Measure continuity, renew broken connections | Masking it by adding anodes |
| Stray current | From shore power or a device | Isolate the source, measure insulation resistance, consider an isolation transformer | Papering over it by changing anodes |
| Ageing battery bank | Capacity loss | Test, replace as a matched bank, set the charge profile | Replacing one battery with a new one |
| Charging profile mismatch | Alternator or charger set wrong for the battery type | Set the profile to the battery chemistry | Leaving it at factory default |
| Hot connection in the panel | Loose terminal | Torque check, renew terminals; verify with a thermal camera | Looking at it and moving on |
11. Plumbing
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Seized seacock | Dezincification in bronze or brass | Renew the valve; compatible material and double clamps | Forcing it open |
| Aged hose | Hardening and cracking | Replace with marine-approved hose, double clamps | Garden hose or a single clamp |
| Bilge pump and float switch | Not working or undersized | Renew pump and switch, add an alarm | Relying on a single pump |
| Air-conditioning raw water circuit | Scaling and blockage | Clean the circuit, service filter and pump | Never opening the strainer |
| Holding tank and lines | Odour, leakage, blockage | Renew tank and hoses; correct the venting | Just using an odour treatment |
| Fuel line and water separator | Water and microbial contamination | Clean the tank, renew filters and hoses | Fitting a new filter without cleaning the tank |
12. Fire and safety
| Finding | What it means | Correct repair | Most common mistake |
|---|---|---|---|
| Extinguisher out of date | Inspection interval passed | Service or recharge at an approved station; automatic system for the engine space | Leaving it in place without checking the date |
| Gas installation leak | Cooker and cylinder circuit | Pressure test, renew hose and regulator, fit a detector | A quick soap-bubble check and nothing else |
| Liferaft and lifejackets | Service date passed | Periodic service at an approved station | Storing it and forgetting the date |
13. Gas, Safety Gear and Comfort Systems
| Finding | What it means | Correct repair | Usual mistake |
|---|---|---|---|
| Bilge pump float switch missing | No automatic protection; water builds up while you are away. | Fit a float switch; wire the pump direct to the battery on its own fuse. | Wiring the pump through the main switch, so it dies when you switch off and leave. |
| No bung beside a seacock | Nothing to hand if a hose bursts. | Tie a tapered softwood bung of the right size beside every seacock. | Keeping all the bungs in one box, with no time to search in an emergency. |
| Single clamp below the waterline | If one clamp fails the hose comes off; ABYC H-27 calls for two. | Two stainless clamps, screws opposed. | Fitting the second clamp the same way round. |
| Emergency steering missing | No alternative if the steering fails. | Carry an emergency tiller and actually try fitting it. | Keeping a tiller aboard that has never been tried. |
| No jackstays or harnesses | Moving on deck at night and in bad weather is unsafe. | Rig jackstays along the deck; provide harnesses and tethers. | Clipping to the guardrail, which is not built for that load. |
| Mooring lines of braided polyester | No stretch; the load goes straight to the cleat and laminate. | Change to three-strand nylon; about 1 mm diameter per 3 m of length. | Carrying on using old sheets as mooring lines. |
| Chafe at the fairlead | Lines wear most here and usually part at this point. | Fit leather or hose chafe guards; end-for-end the line each year. | Cutting off the worn part and shortening the line. |
| Gas locker drain blocked | Leaking gas cannot escape and collects in the locker and bilge. | Clear the drain; confirm it exits overboard above the waterline. | Plugging or taping the drain, which disables the whole system. |
| Gas hose unstamped or cracked | The hose is past its life and may burst under pressure. | Replace with standard-stamped hose; keep free lengths short. | Using garden or fuel hose. |
| Gas detector mounted high | LPG is heavy and sinks; a high detector misses the leak. | Move the sensor down to bilge level. | Confusing it with a CO detector; they are different and mounted at different heights. |
| Fire extinguisher out of date | Pressure may have dropped; it will not work when needed. | Have it refilled; check the gauge yearly. | Keeping it at the back of a locker, where an unreachable extinguisher counts as none. |
| Liferaft service overdue | Inflation system and contents may no longer be reliable. | Periodic service at an approved station. | Postponing service, which can leave you outside the policy's cover. |
| Flares expired | They become unreliable to fire. | Renew; hand the old ones in properly. | Leaving old flares aboard, where they are useless and a risk. |
| Air-conditioning seawater circuit leaking | Salt water drips into the bilge; a source of corrosion and stray current. | Renew hoses and clamps; check the pump seal. | Wiping up the leak without finding its source. |
| Fridge compressor never stops | Insulation failed or gas leaking; it drains the battery bank. | Check insulation and seals; recharge refrigerant if needed. | Hiding the problem by adding battery capacity. |
| Water tank smells | Biofilm has formed; tank and lines are contaminated. | Drain, disinfect with a suitable product, renew filters. | Cleaning the tank and skipping the pipework. |
| Permanent smell from the toilet line | The hose has become permeable. | Replace with odour-resistant sanitation hose. | Using deodoriser to put off the hose change. |
| Water pump cycling often | A leak in the system or low accumulator pressure. | Find the leak; set the accumulator pressure. | Fitting a bigger pump; the leak remains, so does the problem. |
| Deck drains blocked | Rainwater lies on deck; frost can crack the laminate. | Clear drains and hoses; clean the inlet strainers. | Pouring water in from above and not checking the rest of the line. |
14. Structure, Deck and Hardware
| Finding | What it means | Correct repair | Usual mistake |
|---|---|---|---|
| Cracks around a cleat | Mooring load taken straight into the laminate, usually from non-stretch lines. | Remove the cleat, fit a backing plate, repair the laminate; change to three-strand nylon. | Tightening the cleat and filling the crack. |
| Damp under deck hardware | Water in through a bolt hole has wetted the sandwich core. | Remove the fitting, oversize the hole, fill with epoxy and redrill. | Running silicone around the top and leaving the wet core inside. |
| Stanchion base loose | Deck laminate fatigued; a fall risk and a direct safety item. | Renew the backing, enlarge the bolt pattern. | Tightening the bolts harder, which crushes the laminate further. |
| Teak deck plugs missing | Screw heads exposed; water goes straight to the layer below. | Renew plugs; measure teak thickness and plan renewal if thin. | Filling the holes with sealant instead of plugs. |
| Hatch seal hardened | Leaks start; stains and mould inside the cabin. | Replace the seal; adjust the hatch clamping. | Trying to soften the seal with petroleum jelly. |
| Staining around a window | The bedding has reached the end of its life. | Remove the window, clean, rebed with a suitable sealant. | Running silicone around the outside, which traps water inside. |
| Fine line at the hull-keel joint | There may have been movement; it must be assessed. | Check bolt torques, look for cracks inside; drop the keel if needed. | Filling and painting over the line. |
| Excess rudder play | Bearings worn; if it grows, steering control can be lost. | Renew bearings; check the stock is true. | Treating the play as normal; it grows every season. |
| Signs of mooring on the windlass | A windlass is not built to take that load; its gearing suffers. | Service the windlass; use a snubber. | Continuing to leave the chain on the windlass. |
| Winch dry inside | Grease has hardened; pawls can slip and the load drop. | Strip, clean, reassemble with suitable grease and oil. | Spraying oil in from outside. |
| Furler stiff | Bearing or alignment problem; the sail cannot be furled in a blow. | Strip and clean; correct alignment and halyard angle. | Forcing it harder to get past the stiffness. |
| Clevis pin not taped | The pin can work out; rig safety directly affected. | Fit a new split pin and tape it. | Treating the tape as cosmetic. |
15. Engine, Drive and Fuel
| Finding | What it means | Correct repair | Usual mistake |
|---|---|---|---|
| Constant drip from the stern gland | A little drip is normal on a traditional packing; a steady flow means it is out of adjustment. | Adjust or repack; check alignment if a dripless seal is considered. | Tightening until it stops completely, which heats and wears the shaft. |
| Vibration under way | Misalignment, a damaged propeller or worn bearings. | Measure alignment, balance the propeller, check bearings. | Masking vibration by changing engine mounts. |
| No water from the exhaust | Impeller or raw-water circuit blocked; serious damage within minutes. | Stop at once; check strainer, impeller and line. | Running on and looking at it in harbour. |
| Water in the fuel filter | Condensation in the tank or water taken on when filling. | Drain the separator, check the tank bottom; fuel polishing if needed. | Changing the filter and ignoring the tank. |
| Soft hose on the fuel line | Non-standard hose degrades in contact with fuel; a fire risk. | Replace with certified fuel-grade hose, double-clamped. | Fitting any hose as a temporary fix. |
| Black dust from the alternator belt | The belt is slipping; charging and circulation are poor. | Check belt and pulley alignment; renew the belt. | Overtightening the belt, which shortens bearing life. |
| Engine mounts collapsed | Alignment goes out and vibration rises. | Renew the mounts and realign the shaft from scratch. | Changing mounts without realigning. |
| Scale in the heat exchanger | Cooling efficiency falls; the engine runs hot. | Remove and clean the exchanger; renew the zinc anode. | Fitting a lower-rated thermostat to hide the symptom. |
| Milky gearbox oil | Water in the oil; a cooler or seal fault. | Find the source, renew seal or cooler, change the oil. | Changing the oil without finding the source. |
| Nick in a propeller blade | Efficiency falls; vibration and cavitation begin. | Remove the propeller and have it balanced or renewed. | Filing the nick and leaving it. |
16. Electrical and Energy
| Finding | What it means | Correct repair | Usual mistake |
|---|---|---|---|
| Green deposit on battery terminals | Corrosion adds resistance; charging suffers and heat builds. | Clean terminals, apply protection, check cable lugs. | Greasing over it without cleaning first. |
| Heat marks in the switchboard | Loose connection or overload; a forerunner of fire. | Renew the connection; confirm cable size and fuse rating. | Fitting a bigger fuse to stop it blowing. |
| No fuse at the battery bank | In a short circuit the cable can glow red-hot. | Fit a main fuse of the right rating as close to the battery as possible. | Counting the switchboard fuse, which leaves the cable in between unprotected. |
| Cables running through the bilge | Contact with water brings corrosion and stray current. | Reroute above the waterline, supported and labelled. | Taping the cables together and leaving them where they were. |
| Anodes wasting fast | Possibly stray current, from a neighbour or your own system. | Measure with a reference electrode, find the source; isolation transformer if needed. | Adding more anodes without looking for the cause. |
| Shore power cable left coiled on the reel | A coiled cable heats up; a known cause of marina fires. | Uncoil it fully; use the right cable size. | Leaving the surplus on the reel. |
| Bonding broken | Potential difference between metal parts; galvanic corrosion speeds up. | Measure bonding continuity and repair it. | Removing the system entirely, which speeds corrosion further. |
| No earth on the inverter output | A shock risk. | Make the neutral-earth connection as the maker's diagram shows. | Leaving the earth unconnected. |
17. Asking for Quotations: How to Write the Scope
The only reason repair quotations cannot be compared is that the scope was never written down. Three prices from three contractors for the same finding usually describe three different jobs. When you ask, state:
- The item number and description from the report, not "hull repair" but "report item 14: delamination 40 × 25 cm, starboard aft".
- Method, which materials, how many plies, which resin system.
- Verification, a condition that measurements and photographs are taken before anything is closed.
- Time and hardstanding, on work that needs drying, who pays for the yard time.
- Warranty, scope and duration in writing.
18. After the Repair: Verification
The record of the work carries as much value as the work. Every repair file should hold: photographs taken before closing up, material invoices and technical data sheets, measurement records where relevant, and the warranty document. Without that file the work is, at the moment of sale, treated as never done, the buyer's surveyor writes "could not be verified".
Frequently Asked Questions
No. We do not sell repair work on a boat we have surveyed and we take no commission from contractors. This page exists so you can turn your report into a scope document.
We give several names and are paid by none of them. The choice is yours; if you want, we inspect the work stage by stage.
Usually class B items. Class A concerns safety and should be rectified first; class C belongs in the ordinary maintenance calendar.
Because they usually describe different jobs. Prices given without method, materials, ply count and drying time cannot be compared. Use the scope list above.
Yes, on request. The inspections that matter most are the ones before anything is closed, before laminate is closed, before wiring disappears behind a lining, before the engine sits on its beds.
Write in. Findings that come up often get added here; yours can be one of them.
Related Pages
Engine SurveyHours, sea trial, overhaulGood SeamanshipPreventing damage in the first placeAll ServicesConsultancy and supervisionWooden Boat Repair MistakesWrong epoxy, wrong fasteningLithium Battery ConversionRenewing the electrical systemGRP / Fibreglass SurveyLaminate, moisture, coreCommon Boat DefectsThe twenty recorded mostReading a Survey ReportFinding classes and negotiationRefit & New-Build ConsultancyOrder of work and supervisionOsmosis SurveyDiagnosis and repair sequenceMarine Survey GlossaryWhat the terms mean
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Send the item number; we will work out together what to ask and what to require in the quotation.
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