
So, this is not a straightforward answer. Bubble testers are a good idea if fitted correctly and maintained. They are a simple and affective way for the boat owner to test the system for leaks without the presence of a gas safe engineer and their manometer.
No. They are not required to be fitted by the boat safety scheme. If an examiner has told you that you need to fit a bubble tester so they can carry out a BSS. Then he/she is lying and needs to be reported to the BSS office (0333 202 1000). They are basically getting you to waste a substantial amount of time and money, because they are not gas safe registered and by law are not allowed to test your boat by means of the gas test point. This is more than likely because your boat is your main residence and comes under different rules to a private pleasure craft.
Yes they can be fitted to most vessels, but only if the gas locker is suitable to accommodate one. Also the total appliance KW must not exceed 12.5kw. If it does exceed this, then the bubble tester would have to be installed in a branch able to be isolated from the main supply line.