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  • You should drive your boat cautiously in the vicinity of divers in the water. Those in the boat should keep an eye out for divers surfacing unexpectedly. 
  • When dropping divers or recovering them into the boat, the engine should be in neutral. After dropping divers, make sure they are well clear of the propeller before engaging gear.
  • BSAC recommends that the coxswain should use an engine kill-cord In accordance with the manufacturer’s recommendations.
  • Dive boats should display the internationally recognised flag ‘Alpha’ when diving is underway to warn other boats to keep clear. It should not be displayed unless diving operations are actually in progress.
  • It’s a BSAC rule that boats used on BSAC events or for authorised branch diving, whether privately owned or not, must have third-party insurance cover, and it is the responsibility of the branch to make sure this is in place for their boats.
  • More information on boats, including what equipment you need to carry, is available in the Combined Diving Associations’ document Guidelines for the Safe Operation of Member Club Dive Boats.

Distress at sea

  • VHF/DSC radio is the primary means of calling the emergency services from a boat when diving at sea around the UK.
    - If someone’s life or the vessel is in danger you should make a Mayday call. 
    - You can either make a voice call on Channel 16 or send a distress alert via Digital Selective Calling. 
    - You should put out a Pan Pan call for serious problems that are not life-threatening.
  • In emergencies, you are allowed to use the radio even if you don’t have a formal licence. If you are unsure what to do, and there are no trained radio operators on board, pressing and holding the red DSC button will send a distress message to the coastguard automatically. 
  • Do not delay calling for help for too long, if you are convinced problems are arising that you cannot control. Several Maritime and Coastguard Agency reports, each year, indicate that some divers leave it too long before raising the alarm. 
  • Alternative methods of alerting the emergency services at sea include
    - Attracting attention by firing flares (do not waste flares, only fire them if you think someone will see them)
    - Mobile phones (but mobiles only works very close to land and if there is signal coverage) it is a good idea to find out the number of the local Coastguard before you set out to sea
  • Boats should have an Emergency call checklist displayed in a location convenient for the radio.

Pots, markers, and fishing gear

  • You should try to avoid diving near lobster or crab pots, or other fishing gear. Not only is there a risk of getting your propeller or divers at the surface caught up in loose line, there are also underwater risks of entanglement for the divers.

Propeller guards

  • A propeller guard, fitted to an outboard motor, gives a degree of protection from injuries to divers.
  • Before fitting a propeller guard, take note of the manufacturer’s recommendations and instructions, as it is possible to cause stress to the gear box and low end of the engine. Some loss of power may result from fitting a propeller guard.

VHF/DSC radios

  • VHF/DSC radios are an important means of communication at sea (see Distress at sea). 
  • If you are using a radio in a non-emergency situation, then the boat should have a marine VHF installation licence, and you will need to have a marine radio certificate of competency yourself (or be supervised by someone who has).
  • VHF radios sold since 1999 must be fitted with, or be capable of being interfaced with, digital selective calling (DSC). DSC sets allow you to call a specific vessel, but they often have a red emergency button that allows someone to automatically call the Coastguard in an emergency. 


  • You should check the weather regularly. There are many good websites providing marine forecasts for several days ahead, and official Maritime Safety Information (MSI) broadcasts (including the Shipping Forecast and Inshore Waters Forecasts) on VHF and the internet. Radio and television bulletins may include MSI, and in some coastal areas where there is a lot of boating activity there may be specialised local marine forecasts which give details of localised variations in weather not shown anywhere else.
  • In general, you should not dive if it is windier than a Force 4 in open seas. 
  • It may be possible to dive safely in much stronger winds if the dive site is sheltered from the prevailing wind, and the boat journey to and from the dive site is navigable in the prevailing conditions. 
  • There may be occasions when the sea state is too rough to dive, even if the wind is ‘only’ a Force 4. There will be many factors that influence this, including what the weather has been doing for the previous few days, what the currents are like in that area, and what the underwater topology is like.
  • As well as the sea state, other aspects of weather can affect diving safety.
    - Fog can be a problem, increasing the risk of lost divers and collisions with other vessels. 
    - Hot, sunny days bring the risk of sunburn and dehydration.
    - Very cold days bring the risk of exposure, and even hypothermia, for divers in open boats. 
  • If you are diving at an unfamiliar dive site, it’s a good idea to talk to someone who is familiar with the local area and weather who may be able to give you tips.

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