I think you will find they are both as bad as each other overall, but differ in the indvidual conditions.
I used to work on the off shore survey boats and we had one man liferafts on the stern to launch if we lost someone and the FRC.
With Ocean Bottom Cable jobs you are laying a weighted cable on the seabed whilst steaming along. Normally there is a 'V' shaped cutter that launches out to sever the cable if needed and the good old axe if you get time to cut someone free from the cable before they go over. With all of this we still lost a guy about 7 years ago and he was wearing a life jacket.
Often the more dangerous the job the better the pay, look at the African diamond minering engineers!