YACHT & POWERCRAFT DESIGN SERVICES

A boat is usually taken on sea trials after launching.  Typically these trials would occur after construction, but before handing over to the first owner, or following a refit or major modification to the vessel.  Such trials will establish whether the performance of the vessel meets the contractual requirements in terms of speed and handling.  There are certain procedures that need to be followed in conducting trials and a naval architect, such as myself, is the ideal person to organise the trials, supervise them, collect the performance data and analyse the results.

Speed and power trials are normally carried out over a measured mile and will establish the true speed of the vessel, after the measurements have been corrected for the effects of the tide.

The photograph top left shows a 31’ Workboat being taken on rough water sea trials following the redesign of the engine and sterngear arrangement to cure a severe vibration problem (see Motor Boats Monthly - June 1996).

Manoeuvring trials are now increasingly common as all vessels need to be sufficiently easy to handle when under power to enable the skipper to use marina berths and other restricted mooring spaces with confidence.  The boat’s response to rudder movements can be established by the use of a zig-zag or Kempf manoeuvre, whilst the directional stability can be assessed by the use of a Dieudonné spiral manoeuvre.  I have carried out these and other manoeuvring trials regularly in recent years and am well placed to perform this work on any type of vessel and make recommendations for the improvement of the design where necessary.

Home Page

Sea  Trials  

Plot of Zig-zag Manoeuvre showing rudder movements and the boat’s response.

A 31‘ Workboat on Sea Trials in the Solent

Yacht & Powercraft Design Services Ltd
 Email:  info@yacht-designer.co.uk
Tel. 44 (0) 1489-583346   Fax. 44 (0) 1489-583346  Mobile  07803-724317