A fast boat puts on its hull in a few seasons the load a slow boat would see over years. Every wave impact works the bottom, the stringers and the transom. So the survey focuses on where the load goes and on behaviour at speed.
Structure
- Bottom
- Stress cracks on the planing surface, especially forward and where stringers end.
- Stringers
- The bond of the longitudinal stringers to the skin; separation or cracking.
- Transom
- On outboard boats, wet transom core and wet around engine bolts; transom flex.
- Deck and console
- Cracks at console and seat mounts; impact loads pass through them.
Propulsion
- Outboards: hours and fault history from an authorised dealer's electronic read-out; gear oil and propeller. A compression test, if needed, is coordinated separately with an independent engine technician.
- Sterndrives: bellows, gimbal bearing and water in the drive oil.
- Hydraulic steering: leaks, play and pump.
- Trim tabs: movement and hydraulic leaks.
On sea trial
Getting on the plane, rpm at full speed against the maker's rating, behaviour in turns and in waves, and the boat's attitude with trim. Speed is read from GPS; at high speed the safety decision rests with the skipper.
What we often see
- Star cracks in gelcoat: Hairline cracks radiating from a centre around cleat and winch bases.
- Wet core in the transom: High moisture readings and a dull sound in the transom around the ladder and exhaust outlet.
Why the bottom needs special care
When a fast boat is planing, the forward and mid bottom take heavy slamming loads every time it hits a wave. Over time these fatigue the bottom laminate and the stringers that carry it. On survey the bottom is sounded and moisture-read with particular care; inside, the bond of stringers to the skin and floors are checked for cracks and separation. A hard-used boat can show separation or cracks in these areas.
Transom and drive
On outboard boats, the transom carries the engine's weight and thrust. A wet core inside the transom, especially around the engine mounting bolts, is a common and expensive problem. On sterndrive boats, bellows condition, drive-leg corrosion and trim are checked; a split bellows can let water into the boat.
Sea trial at speed
On the sea trial, time to plane, top speed and rpm, steering at speed and behaviour in turns are observed. Trim and tabs are tried. Vibration at speed usually points to a propeller or shaft problem.
Fuel system
Fast boats burn a lot of fuel and their fuel systems work hard. Hoses, filters and tank connections are checked; on petrol boats, engine compartment ventilation and precautions against fuel vapour matter especially.
Usage history
Engine hours, fuel records and service invoices tell how the boat has been used. A boat that ran many hours in a short time and one lightly used over many years carry different problems.
In the report
Bottom, transom and drive are covered in separate sections; each finding comes with photo and grade.
Steering at speed
Steering gear takes high loads at speed; play in cables, hydraulic leaks or stiffness are checked ashore and felt on the trial.
Steering that responds late or with play at speed is graded as a safety finding and must be put right before the boat is used at speed again.
A fast boat that has been well looked after is a joy; the survey's job is to tell the two apart before money changes hands.