Fishing vessel stability

Unstable vessels are a leading cause of death among commercial fishermen. These tips could save your life.
Bridlington lifeboat crew rescue four fisherman from their sinking boat

Photo: RNLI / Andy Brompton

Bridlington lifeboat crew rescue four fisherman from their sinking boat

Understand the risks and stay safe at sea

Between 2010 and 2013, capsize, leaking or swamping accounted for 57% of commercial fishing fatalities in the UK and Ireland. 

Leaks, overloading and the free surface effect of a loose catch or poorly stowed kit can all make a fishing vessel unstable.

By keeping your vessel’s stability in mind throughout a trip, you can significantly reduce the risks.

Don’t wait until it’s too late to find out the tipping point of your fishing boat – follow these simple steps to being safer at sea.

Our series of videos will take you through some simple checks to keep your vessel stable.

Vessel modifications

Modifications to your boat, such as installing new fishing equipment or changing internal layout, can affect its stability at sea. Find out what effects these changes can have – and how to counteract them.

If you’re planning to make changes to your boat:

  • ensure adequate freeboard
  • consider weight creep (also known as stability creep) when working out the maximum load allowed
  • consult an MCA surveyor, naval architect or Seafish Marine Services before any major changes, whether it’s an addition or position change. Get free advice at or email

Free surface effect

Loose kit, fish and excess water on or below deck can all shift and raise your boat’s centre of gravity. If left unchecked, the effect of their movement can capsize your fishing boat within minutes. Find out how to avoid the problem before it develops.

Next time you’re on your boat make sure you:

  • check all scuppers/freeing ports are open and clear
  • stow catch and loose gear securely at all times, preferably below deck
  • keep it watertight: check critical pipework, stern and rudder glands before each trip and check bilge alarms regularly.

Hauling operations

Hauling in your catch can change your boat’s centre of gravity and have a serious impact on its stability. This film helps you understand how to avoid some of these impacts.

Make sure you:

  • check shackles/blocks and wire regularly
  • check quick release on the beam trawl poles
  • consider using safety chains on hauling blocks
  • only permit trained, experienced people on the winch/power block and net drum
  • take great care when hauling before tide and wind when fast to seabed.


Overloading your fishing vessel reduces its freeboard and creates a lack of reserve buoyancy. We show why it’s never worth pushing your luck – and look at the pros and cons of using a Wolfson mark for stability.

Next time you’re on your boat make sure you:

  • have plenty of reserve freeboard: the Wolfson mark is an optional aid to check this
  • stow catch as low as possible
  • check crew understand your vessel’s stability book, if it has one.

Watertight integrity

Flood water, combined with its free surface, can rapidly affect your boat’s stability. Get the facts to help keep your fishing vessel watertight.

Make sure you:

  • regularly inspect critical pipework, rudder and stern glands, and bilge alarms for defects
  • replace them if necessary
  • regularly check that hatches, doors and scuttles are correctly sealed, even in good weather
  • have a damage control kit to hand.

For more support and advice contact Seafish.

Statistics are based on RNLI-commissioned casual analysis of 44 fatalities between 2010 and 2013. Of these fatalities, 15 were caused by vessel capsize and 11 were due to leaking, swamping or sinking. All data is based on RNLI return of service records 2009-2013.

Don’t be a statistic

57% of commercial fishing deaths in the UK and Ireland were caused by unstable boats between 2010 and 2013