The Boat Floats

Guide

Keeping Your Canal Boat Safe in Extreme Weather

Canals are sheltered compared to open water, but extreme weather still affects boats: storms, high winds, flooding, ice, prolonged heatwaves. This guide covers

4 min read · Updated 2025-12-01

Keeping Your Canal Boat Safe in Extreme Weather

Canals are sheltered compared to open water, but extreme weather still affects boats: storms, high winds, flooding, ice, prolonged heatwaves. This guide covers what each does, how to prepare, and what to do during.

Storms and high winds

Wind affects boats more than people expect. A 60ft narrowboat is a sail in a side wind.

Before:

  • Double-check mooring ropes and add a spring line if you don't have one
  • Refresh fenders to absorb impacts against the bank
  • Move loose items off the cabin top
  • Check the boat is secure against bank, not pulling away
  • Stow the chimney cowl if winds will be severe

During:

  • Don't try to cruise in winds above ~25mph; boats become uncontrollable, particularly at locks and bridges
  • Stay on board if comfortable and warm; let the storm pass
  • Listen for any rope chafe or thumping that suggests something is loose

After:

  • Inspect mooring ropes for damage and replace if frayed
  • Check the cabin top and roof items
  • Pump bilge if any rainwater has got in

Flooding

Heavy rain can swell rivers and some canals to the point of cancellation. CRT and the Environment Agency post stoppage and flood notices online and on social media.

Before:

  • Watch the forecast and warning levels
  • Move off river sections to canal if possible
  • Add longer mooring ropes - water level may rise faster than you can adjust short lines
  • Set your bilge pump to automatic
  • Check insurance covers flood

During:

  • Don't cruise on rising rivers (currents become dangerous, debris in water)
  • Don't moor under trees (debris falls)
  • Watch for loose floating objects upstream
  • If a flood warning is in force, prepare to leave the boat for higher ground

After:

  • Inspect mooring lines and any damage
  • Check the bilge for muddy water (suggests breach)
  • Engine air filter - check for water if water rose high

Ice

Frozen canals are common in cold winters.

Before freezing:

During:

  • Don't cruise (ice damages paint and propellers, and CRT often closes the navigation in deep ice)
  • If ice is around the boat, no need to break it; let it melt naturally
  • Keep heating running (or sufficient to prevent internal frost)

When the thaw comes:

  • Inspect hull paint for damage at the waterline
  • Check stern gland after first cruise

Heatwaves

Summer extremes affect boats too:

Before:

  • Move the boat into shade if possible
  • Top up water tanks (heat increases consumption)
  • Check fridge ventilation isn't blocked

During:

  • Open windows and skylights overnight to cool the cabin
  • Run engine briefly each day to keep batteries charged (fridge runs harder in heat)
  • Watch for water level drops on water-stressed canals
  • Use minimal water (showers, washing up)
  • Drink lots of water; the cabin can be 35°C+

After prolonged heat:

  • Check that the propeller and stern gear haven't picked up debris from low water
  • Top up coolant and check engine ran clean

Drought and water restrictions

In dry summers, navigation authorities sometimes restrict cruising hours or close locks (especially staircase flights) to conserve water.

  • Check stoppage and water level notices before setting off
  • Plan routes around restricted areas
  • Don't run aground; some canals get very shallow

Lightning

Rare to be hit on a canal but possible:

  • During thunderstorms, stay inside the cabin
  • Don't grip metal handrails outside if a storm is overhead
  • Modern narrowboats are essentially Faraday cages (steel hull and cabin) - safe inside

Snow

Cosmetic mostly:

  • Sweep snow off the cabin top to avoid weight
  • Salt the towpath edge near your mooring (where permitted)
  • Take care on icy gunwales and lock-side stones
  • Stove or central heating will need more fuel; stock up before snow

Insurance

Check your insurance covers:

  • Storm damage
  • Flood damage
  • Frost damage (often excluded if "due to lack of winterisation")
  • Salvage costs

If your boat is laid up for winter, notify the insurer; some require the boat to be winterised or premiums adjust.

A bad weather checklist

  • Mooring ropes and fenders refreshed before any storm
  • Bilge pump on automatic
  • Fuel/coal/wood topped up before cold snap
  • Forecast and CRT notices monitored
  • Insurance covers extreme weather
  • Heating working and serviced
  • A flask, food and water on board for snowed-in days

Conclusion

Canals shelter boats from the worst of the weather, but extreme conditions still need preparation. Strong moorings, a working bilge pump, a heated and winterised boat and a watch on the forecast cover most situations. The most damaging weather is usually predicted in advance; a few hours of preparation in the days before saves much larger problems during.