They'd much rather educate you first than rescue you later. Visit a Royal National Lifeboat Institution Station. Bear in mind that they are a charity, and you may be able to help their fund raising. Boat builders and sail makers HM Customs and excise Harbour masters, port controls, coast radio stations Royal Naval ships and shore establishments Merchant ships in harbour Ferry companies may be able to offer a tour of a boat in port, or a visit to the bridge at sea. Powerboat trips to various places, e.g. walking on the Goodwin sands at low tide.
Many museums have a maritime aspect.
A definite aim helps keep attention. There are many useful links and addresses in the activity links index. HM Coastguard are a good source of posters, advice, training etc. Their web site contains many useful links to training material. The RNLI can provide many posters and leaflets on sea safety from their national office.