AW BYRDE & ASSOCIATES

Yacht  Surveys & Small-Craft Surveys

Associate Member of the Yacht Designers & Surveyors Association

Sea Trials

Sea Trials

Structural condition yacht surveys do not include a sea trial, but craft can be trialled at extra cost, usually at an hourly rate because the amount of time needed cannot always be predicted.

The purpose of a survey sea-trial is to check the yacht's performance and systems operation: it is not to see if the Buyer likes the yacht.

There may be an opportunity to test some items when for example a boat is moved between her berth and the crane dock, but that does not constitute a thorough trial.

I carry out sea-trials of many different types of craft. I need a competent (and insured) skipper to operate the boat: for a pre-purchase sea trial that will usually be the Broker or the Owner. I will to be too busy during the trial to attend to handling the boat or navigation (although I am of course always very willing to  handle lines etc).

The vessel must of course be presented for trials in a seaworthy state.

It may often make sense for a qualified Marine Engineer also to accompany a trial once the structural survey has been completed, particularly on motor craft. I know a considerable amount about engines, gearboxes and outdrives: enough to know that you really cannot assess their mechanical state by an external inspection alone, even during a run. A marine engineer qualified to work on the make of engine, and familiar with them, will also ensure all the Manufacturer's Service Bulletins have been completed. That is most important: at least one manufacturer issues only Service Bulletins when a Product Recall would be much more appropriate.

The scope of the sea trial varies with the type of vessel, but for a twin-engined power-craft would include some or all of the following as appropriate:

• Starting from cold

• Security of components and leaks when running

• Instrument readings at cold and at working temperature, and at intervals up to full power

• Operation of governors

• Calibration of the ship's tachometers against the surveyor's hand-held tachometer

• Recording maximum RPM achieved and the speedometer reading, cross-checked by the surveyor's GPS

• Ability to hold full power on both engines for 10 minutes without overheating, losing oil pressure, excess smoke, etc

• Inspecting mountings and beds while under load and when turning under ahead and astern up to cavitation RPM

• Getting a guide to propeller sizing by recording RPM achieved with each engine running alone

• Checking for shaft alignment and straightness by ensuring they turn of their own accord when in neutral, accelerating under one engine alone from stationary

• Checking the rudders, trunks & glands (and ballast keel mounting points on a sailing yacht) when running an S-bend course at speed

• Checking for smooth quiet and positive operation of gearboxes or outdrives

• Checking the hull and deck structures for movement when under power

• Checking navigation instruments etc.

Motor yachts that will not achieve full revolutions need further investigation. The trial will not be representative unless the hull is free of fouling growth, the antifouling paint scheme is smooth, and the propellers are in good condition.

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Copyright © 2005 AW BYRDE & ASSOCIATES.

AW Byrde & Associates is the trading name of Stonebarrow Surveys Ltd, Company Number 4783927 Registered in England. Office Address: Stonefield, Kimmeridge, Wareham, Dorset, BH20 5PE United Kingdom

Last modified: 02/22/09