Sea State – A Definition

Sea State refers to the conditions found on the surface of the water as caused by the combination of levels of wind and/or swell (or lack of).

Sea State Descriptions

The Douglas Sea Scale was devised by a Royal Navy Admiral in 1917, H.P. Douglas. It is a system for estimating the sea’s roughness for navigation purposes. It has been adopted by the Met Office, and in kayaking circles by paddlers and the BCU who refer to it when trip planning and for the remit of various awards. His scale runs from 0 (0.0m calm, glassy) to 9 (Over 14.0m Phenomenal).

For the majority of sea kayakers, Sea States 0-5 are most relevant and are summarised in this table which uses the recognised Met Office breakdown along with some useful ‘sea kayak’ specific descriptions from Calum McKerral.

Sea State Description Wave Height Kayakers Rough Guide
0 Calm – Glassy 0 Metres No waves
1 Calm – Rippled 0-0.10 Metres Up to deck seam (depending on load and/or kayak design)
2 Smooth 0.10 – 0.50 Metres Between deck seam and armpit height (approx)
3 Slight 0.50 – 1.25 Metres Between armpit and paddle-top height (approx)
4 Moderate 1.25 – 2.50 Metres Kayakers with paddles up disappear in troughs
5 Rough 2.50 – 4.00 Metres

Gauging Sea State

Sea states are utilised as part of many coastal weather forecasts or shipping forecasts but can often be tricky to fully understand/appreciate as currently many references are still images in reference books.

The following video from Calum Mckerral and Simon Willis has been produced to overcome this problem and act as an aid for Sea Kayakers in gauging sea state. The video is part of Calum’s work towards completing his BCU Level 5 Sea Coaches award. Be aware that his heights vary ever so slightly from those used by the original Douglas Sea Scale/published Met Office heights. There is also a useful .pdf document that can be downloaded from Simon Willis’s website.

Useful Links for Learning More About Sea States

Wikipedia – Sea States Entry on Wikipedia
Met Office – Glossary for Weather Forecasts
UK Sea Kayak Guidebook Almanac – A range of weather related links/downloads including sea state
Met Office Factsheet – Beaufort & Sea State Scales
Sea Kayak Podcasts – Simon Willis’s excellent set of interviews