Wake Wash

31st October 2007

Wake Wash

Initial Report

Report text:

This is about particular ships which sail regularly into this port. Complaints have been made via the radio directly to the ships involved and by telephone to the harbour master and I believe by letter. The ships are both quite big ships for using the channel.  The problem arises if they arrive or leave at low water, as they can set up a 3-4 foot wave which has washed people out of their dinghies and which will pick a boat up which may be just afloat or aground and throw the boat sideways with incredible force. I am talking about 20-30 ft boats. Some of the captains come through at a slow sensible speed and do not cause a problem. Other captains come through faster. Sooner or later someone is going to get washed overboard or get washed out of their dinghy and drown. There have been several instances. A letter came out from the harbour master warning people to wear life jackets because of this problem, but if it is possible for large vessels to navigate the channel on most occasions without causing a problem, why cannot this be the standard practice.

CHIRP Comment:

CHIRP has corresponded with the Harbour Authority.  The Authority is very aware of the issue and has provided feedback which we summarise as follows:

  • The Authority has records of the passages of vessels passing various reporting positions. These indicate that in general vessels are maintaining a safe speed in the upper reaches of the river where the wash effect is at its greatest.
  • All Masters are Pilotage Exemption Certificate holders and as part of their oral examination and as part of their practical assessment are tested on their understanding of this effect.
  • In recent years with the advent of AIS the Authority can now obtain a direct readout of a vessels speed which is recorded onto hard drive. Masters and Pilots are aware of this and are even more unlikely to speed in the river.
  • The rushing of water from the shallow bank of this river as a large ship passes can be very disturbing to other vessels. The effect is most pronounced at low water but there are other factors.
  • The Authority has issued a local notice to mariners and a warning in the local yachting guide.

To CHIRP, the way forward appears to be:

  • The Harbour Authority to continue to emphasise to Masters and Pilots the need to proceed at slow speed – monitor speeds of vessels and make visual checks on the effect of wash
  • The owners of small craft to remain observant to the approach of large vessels and alert to the possibility of wash.
  • The Harbour Authority to consider highlighting again the dangers of wash at low water by re-issuing and/or updating the relevant Notice to Mariners.
  • People in small craft to consider wearing lifejackets at all times, as recommended by the RNLI.
  • Harbour users to report any problems to the harbour Authority at the time of the occurrence or as soon after as possible.
  • If a serious problem persists, a more fundamental review of the issues and mitigating measures may be required.

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