Marine helmets are designed to protect your head! CE Marked PAS028 helmets were more specifically designed for marine environments, they float, protect you from marine specific hazards, and keep your head warm.

Whilst some use ‘canoe helmets’, in fact often anything with a CE mark to keep within the law. The smart people (coastguard agencies, military units, the police and the RNLI) wear PA028 helmets.

Gecko MK11

The ‘original’ marine safety helmet designed by Gecko, in Bude Cornwall for the RNLI & Met Police.

Over many years it has evolved into the MK11 helmet.

Future Safety Blue Ray

A relative newcomer the Blue Ray is made of carbon fibre, so exceptionally light. And without the inflatable bladder of the Gecko, often regarded as more suitable in extremes of temperature

Again through feedback and evolution, the current Blue Ray is an excellent helmet.

https://en.wikipedia.org/wiki/British_Standards#PAS_Documents