Dont know me old matee,Sorry for sounding a bit sarki as I was in a rush and it was not intended.
There is a crossover at the moment and the Sea areas are mesured by the expected wave height beleived to be encountered eg cat c 2mtr cat B 4 mtr.
As most larger ribs are in my oppinion great sea boats then it is my oppinion that there should be no restrictions placed on a individual, as to what he can use his boat for,as it is taking the responsibility away from me and assumes that somebody is better placed to make those decisions. I object to someone else believing they can make decisions for me or my family on my behalf with regardes to safty issues. The point I am trying to make is if you want to use your boat offshore in conditions that may encounter waves of more than 2 mtrs then buy a cat B boat.If you dont want to go offshore and believe you will not encounter waves more than 2mtrs height the a cat C boat will be fine.I reality you will hopefully be ok in a cat C well prepared rib in larger waves than cat C conditions dictate as most ribs are so versatile and have such good built in saftey characteristics. What will be on interest is what areas are deemed cat C areas and what areas are deemed cat B areas according to the weather man/MCA/insurance people.As I dont know.
On the Cabin rib thing then its doughtfull you will find a cat C cabin rib unless you are realy unlucky,as most people who want to use a cabin rib will also want to go offshore in it.We are based in Blackpool and for us to get to irland/isle of man we have to cross the irish sea which is renowned for larger wave than 2 mtrs so,if you want to go offshore from here then its Cat B for easy ins cover without worrying about are you coverd properly or what happens if the condition change half way over IMHO. I dont know the answere to the question on what happens if you want ins cover and you dont have a RCD cat B catergorised boat at present for this sort off Sea area.I will enquire on Monday.
Maybe somebody could tell us have they had any problems insuring a RIB for leisure use this yr for offshore Sea conditions eg waves bigger than 2 mtrs?.And can they recomend an insurer who will insure a cat C boat with no restrictions/ limitations as to its use or its sea area being defined in the small print.
Hope this helps.