In the past it worked like this and I doubt its changed much. The oil companies contracted with the supply boat owners to provide services to their rigs. The oil companies had specifications out the wazoo which the supply boat companies had to agree to, everything from the DP class to the amount of mud they could provide, recorded safety record plus MUCH more. The supply boat owners could either meet the qualifications or be left out, there was some ole boy glad handing involved as there is in any business decision but the rules were pretty strict. The rate the oil companies are willing to pay for the supply boats is just a portion of the cost to drill per day and each portion adds to the total cost with the biggest cost being the drilling rig itself. Though day rates for rigs is going up they still are not near the rates of 10 years ago. Hence I don’t see supply boat or drillship wages getting close to the previous highs any time soon. But one might get in now and ride the wave if it comes and come out very well.