Hampshire Constabulary Marine Unit have produced a useful leaflet sumarising all the speed limits in the harbours and rivers around the Solent. This is helpful because they differ, and signage is often small or obscured. You can download a copy of the leaflet here.

COLREGS Rule 6 – Safe Speed

Every vessel shall at all times proceed at a safe speed so that she can take proper and effective action to avoid collision and be stopped within the distance appropriate to the prevailing circumstances and conditions.

The following factors should be among those taken into account:

  1. The state of visibility
  2. The traffic density including concentrations of fishing vessels or any other vessels
  3. The manoeuvrability of the vessel with special reference to stopping distance and turning ability in the prevailing conditions
  4. The state of wind, sea and current, and the proximity of navigational hazards
  5. At night the presence of background light such as from shore lights or other back scatter
  6. In instances where radar is being used, the limitations associated with your radar device and general radar navigation must be considered