Originally Posted by BogMonster
What governs whether somebody uses A or B?
I don't think traffic congestion is an issue here
I didn't think congestion would be an issue for you, thought I had better cover all the bases just in case
Class A is an IMO / SOLAS requirement for big ships (300 tons+?) and all (international?) passenger ships. If you are not mandated to have class A, I think it is just personal choice - however class A is a lot more expensive than class B, and has extra requirements - for example class A has to have its own VHF aerial, class B can use an aerial splitter to share a VHF radio aerial.
For an open boat, I am not aware of any waterproof class A transceivers - there are a few options for waterproof class B.