Contact made by tractor tug Svitzer Constance with lock gate

Location: King George Dock, Hull, England.

Completed PE Summary: Svitzer Constance

A short summary of the accident and action taken:

Vessel name:   Svitzer Constance
Ship Owner:   Svitzer Humber Ltd
Port of Registry:   Hull
Flag:   United Kingdom
Type:   Voith Schneider Tractor Tug
Built:   1982
Construction:   Steel
Length overall:   30.2m
Gross tonnage:   285
Date & Time:   9 March 2009, 1345 UTC
Location of incident:   King George Dock lock, Hull
Incident Type:   Contact
Persons onboard:   3
Injuries/fatalities:   None
Damage/pollution:   Penetration damage to starboard quarter in way of freshwater tank and rope hold, and damage to the winch; minor damage to lock gate and gate recess.


The harbour tug Svitzer Constance was assisting with the entry of the Finnish-registered 11,530 gt ro-ro cargo vessel Finnhawk into King George Dock, Hull. Svitzer Constance was connected to the port aft mooring station on Finnhawk. This was to counter both the wind, which was gusting to force 5, and Finnhawk’s inoperative stern thruster; there was also no centreline aft fairlead available on Finnhawk. As the two vessels began to exit the lock into the dock, Svitzer Constance’s stern was pushing on the port side of Finnhawk’s stern. However, as the tug approached the inner lock gates, her stern slipped off. No longer in push mode, her skeg was affected by Finnhawk’s wake, causing her stern to shear towards one of the inner lock gates. The shear was exacerbated as the tow wire, with a particularly high lead angle to Finnhawk’s mooring station, became taut.

Despite an emergency avoiding manoeuvre, Svitzer Constance made heavy contact with the lock gate and gate recess, hanging up on the latter for around 20 seconds and, in turn, causing the tow wire to part as Finnhawk continued into the dock. Svitzer Constance was able to manoeuvre off the recess, and her crew conducted an initial damage assessment. She then continued to assist with berthing Finnhawk in push mode before returning to her own berth. Svitzer Constance experienced no flooding, with all of the damage above the waterline. Minor damage was sustained to the lock gate and gate recess.

Action taken

ABP Humber has circulated a Notice to Pilots to all pilots and Pilotage Exemption Certificate (PEC) holders, summarising the accident and stating various future measures, including:

  • Proper concise planning is to be agreed between bridge teams and tugs, together with clear and unambiguous communication, to ensure safe operations.

  • The practice of tugs pushing up on the stern of ro-ro ferries is not to be allowed under normal circumstances.

ABP Humber also intends to mark both sides of the locks at Immingham and Hull, to provide warning to tug skippers that they are approaching the gate recess and to take extra care to reduce the risk of shearing.

Svitzer UK has circulated a safety memo to all Svitzer UK ports, summarising its internal investigation report for the accident and incorporating a number of recommendations, including:

  • Cessation of the practice of tugs pushing up on the transom of vessels to exert a steering force.

  • Reiteration of the use of towing winch emergency release systems as a preventative rather than emergency action, once an incident has developed.

Published: June 2009

Published 23 January 2015