Are you asking about a cruise ship or aircraft if the latter which airline .
Are you going on a fly-cruise or a cruise out of the UK? If it is a fly-cruise it will depend on the airline. You may be lucky if it is an exclusive charter and be given a larger baggage allowance. If it is a cruise ex-UK there is virtually no limit although the formal amount is 200 k. Fred. Olsen will give you full details with your documentation.