You have to remember I am used to steam driven military aircraft where everything has to be bolted on the outside because capability is always an afterthought - that's why I asked the question.
I presume it is a weather radar - is it cleared for IMC operations below safety alt over the water?
Night Watchman - the problem with having a radar that only looks forward is that you can only do night/IMC letdowns to cliffs/boats etc that are ahead of you. Try doing a letdown into a bay with a 40kt onshore wind and you will find that having an (almost) 360 degree radar is an awful lot more useful. Equally the ability to see all around you in a congested environment (lots of vessels, buoys, rigs etc) at night or in IMC at low level gives you much more SA and flexibility.