Buying a used boat is exciting – but skipping a proper inspection can turn your dream into an expensive nightmare. Even a boat that looks great on the outside can hide serious problems below the waterline, in the bilge, or in the electrical system.
This checklist covers the 10 most important things to inspect before you make an offer. Whether you’re a first-time buyer or an experienced sailor, these checks will protect your investment and give you the confidence to negotiate from a position of knowledge.
1. The Hull – Outside and Below the Waterline
The hull is the most important structural element of any boat. Start here.
What to check:
- Walk around the entire boat and look for cracks, crazing, or deep scratches in the gelcoat
- Look for any repairs that have been filled and painted over – these can indicate past collisions or groundings
- Check the keel attachment area carefully – cracks around the keel bolts are a serious warning sign
- If the boat is in the water, arrange a haul-out to inspect the bottom properly
Red flags:
- Large areas of osmotic blistering (small bubbles in the gelcoat below the waterline)
- Cracks around the keel that extend into the hull
- Evidence of major repairs that haven’t been disclosed
Pro Tip: Osmosis sounds alarming but is often manageable. A professional surveyor can assess the severity with a moisture meter and give you a realistic repair cost.
2. The Deck – Soft Spots and Water Ingress
A soft or spongy deck is one of the most common – and most expensive – problems on used fiberglass boats.
How to check:
- Walk slowly across the entire deck, applying firm pressure with each step
- Pay special attention around the mast base, chainplates, stanchion bases, and winches
- Press firmly – a solid deck will feel hard; a delaminated area will feel soft or slightly springy
Why it matters: Deck delamination occurs when water enters the core material (usually balsa or foam) through poorly sealed fittings. Once wet, the core rots and loses its structural integrity. Repairs are expensive and time-consuming.
What to do: Any soft spots should be assessed by a professional surveyor with a moisture meter before you proceed.
3. The Bilge – The Boat’s Health Report
The bilge is the lowest part of the boat’s interior and collects whatever leaks, drips or seeps in from above or below. It tells you a lot about the boat’s condition.
What to check:
- Is the bilge dry or wet?
- Is there oil in the bilge water? (indicates engine or gearbox leak)
- Is there rust, which would indicate steel components corroding?
- Does it smell strongly of mildew or fuel?
What you want to see: A clean, dry bilge with no oil sheen and no strong odours. This indicates the boat has been well cared for and has no active leaks.
Red flags:
- Standing water with an oil sheen
- Strong fuel smell (possible tank or fuel line leak)
- Heavy rust on the bilge pump or structural frames
4. Through-Hull Fittings and Seacocks
Through-hull fittings are holes in the hull – each one is a potential entry point for water. They must all be fitted with functioning seacocks (valves) that can be closed in an emergency.
What to check:
- Locate every through-hull fitting (typically: engine raw water intake, cockpit drains, toilet inlet/outlet, sink drain)
- Try to operate each seacock – it should turn smoothly and close completely
- Check the fitting for corrosion, especially if it’s made of bronze or plastic
- Look for any signs of weeping or leaking around the fitting
Red flags:
- Seacocks that are seized open and cannot be closed
- Plastic through-hulls that are discoloured or brittle
- Any sign of active leaking around a fitting
Pro Tip: Seized seacocks are a safety issue, not just a maintenance issue. Factor in the cost of replacement when negotiating the price.
5. The Engine – Hours, Service History and Condition
The engine is one of the most expensive components to repair or replace. A thorough engine check is essential.
What to check:
- Ask for the service history – when was the last service, impeller change, belt replacement?
- Check the engine hours (low hours aren’t always better – an engine that rarely runs can suffer from lack of use)
- Start the engine cold and watch the exhaust: white smoke on startup is normal, but persistent blue or black smoke is not
- Check for oil leaks around the engine block, gearbox and mounts
- Run the engine at operating temperature and check for overheating
- Check the raw water cooling – water should flow clearly from the exhaust outlet
What you want to see:
- A service history with regular oil changes
- Clean engine compartment with no major oil leaks
- Clear exhaust water with no excessive smoke
- Smooth gear engagement in forward and reverse
Red flags:
- No service records
- Excessive oil in the bilge beneath the engine
- Overheating at low RPM
- Difficulty engaging gears
6. The Standing Rigging – Safety Critical
The standing rigging (shrouds, forestay, backstay) holds the mast up. Failure at sea can result in a dismasting – one of the most dangerous situations a sailor can face.
What to check:
- Look at every swage fitting (where the wire terminates) for cracks or corrosion
- Run your hand along the wire – feel for any broken strands (they will cut your hand if present)
- Check the chainplates where the rigging attaches to the hull – look for cracks in the deck around them
- Ask when the rigging was last replaced
General rule: Standing rigging should be replaced every 10 years regardless of apparent condition, or after any significant offshore passage. If a boat has original rigging from the 1990s or 2000s, budget for immediate replacement.
Cost to budget: Full standing rigging replacement on a 35–40 ft boat typically costs €2,000–€5,000 including labour.
7. The Sails – Condition and Age
Sails are expensive. A full set of sails for a 35 ft boat can cost €5,000–€15,000 new. Always inspect them carefully.
What to check:
- Ask the seller to unfurl or hoist every sail so you can inspect them
- Look at the stitching along the seams – UV degradation causes thread to fail before the sail cloth
- Check the corners (head, tack, clew) for wear, tears or reinforcement patches
- Look at the luff tape on furling headsails for wear or damage
- Ask about the age of the sails
What you want to see: Sails that are clean, evenly coloured (no significant UV bleaching), with tight stitching and no tears.
Red flags:
- Sails that are stiff, discoloured, or have loose stitching
- Missing or damaged battens
- A furling headsail that won’t unfurl properly for inspection
8. The Electrical System
Electrical problems are one of the most common issues on used boats – and one of the most dangerous.
What to check:
- Test every switch panel – navigation lights, interior lights, instruments, VHF radio
- Check the battery bank – how old are the batteries? Do they hold charge?
- Look at the wiring in the engine compartment – is it tidy and properly secured, or a chaotic mess of added wires?
- Check the chart plotter, autopilot and other electronics for function
- Look for any signs of corrosion on connections and terminals
Red flags:
- Wiring that has been added randomly without proper fusing
- Corroded or melted terminals
- A battery bank that won’t hold charge
- Non-functioning navigation lights (a legal requirement)
Pro Tip: A messy or improvised electrical system is a fire risk. If the wiring looks chaotic, factor in a full rewire in your cost assessment.
9. The Interior – Moisture, Mould and Comfort
The interior condition tells you a lot about how the boat has been used and maintained.
What to check:
- Open every locker and cupboard – smell for damp or mildew
- Check the headlining (ceiling panels) for staining, which indicates deck leaks
- Look at the cushions – are they dry or damp? Do they smell?
- Check the galley: does the stove work? Is the plumbing functional?
- Test the toilet (head) – does it pump properly?
- Check the freshwater system – any leaks, and does the pump work?
What you want to see: A dry, fresh-smelling interior with no visible mould or water staining.
Red flags:
- Strong mildew smell throughout
- Water staining on the headlining or bulkheads
- Mould on cushions or in lockers
10. Documentation and Legal Status
Finally – and critically – verify that the paperwork is in order before any money changes hands.
What to check:
- Proof of ownership – The seller must be able to prove they own the boat
- Registration documents – Is the boat registered? In which country?
- VAT status – In Europe, confirm that VAT has been paid (or that the boat is VAT-exempt). This is essential for sailing legally within EU waters
- Any outstanding liens or mortgages – In some countries a boat can be sold with a debt attached to it
- Insurance history – Any major claims should be disclosed
Pro Tip: Never hand over money until you have verified ownership and VAT status. If the seller cannot produce these documents, walk away.
Your Inspection Checklist – Summary
| # | Area | Key Check |
|---|---|---|
| 1 | Hull | Osmosis, cracks, keel attachment |
| 2 | Deck | Soft spots, water ingress around fittings |
| 3 | Bilge | Dry, no oil, no strong odours |
| 4 | Through-hulls | All seacocks operate freely |
| 5 | Engine | Service history, no leaks, clean exhaust |
| 6 | Standing rigging | No broken strands, age of rigging |
| 7 | Sails | Condition, stitching, age |
| 8 | Electrics | All systems working, tidy wiring |
| 9 | Interior | Dry, no mould, all systems functional |
| 10 | Documents | Ownership, VAT, no liens |
Use it at the viewing: our free boat inspection checklist covers 78 points – tick them off on your phone (saved automatically) or print the PDF.
When to Walk Away
No matter how much you like a boat, walk away if:
- The seller refuses a professional survey or sea trial
- Multiple major issues are found and the seller won’t negotiate
- The documentation is incomplete or unclear
- Your gut tells you something is wrong
There will always be another boat. Patience is the most valuable tool in any boat buyer’s toolkit.
Ready to start your search? Browse current listings on boatmarket24.com – new boats added regularly, no commission, no hidden fees.
