You're correct, as a marine engineer, I can tell you that the biofouling problem is far from solved. To date, copper biocide works best, but is terrible for the

You're correct, as a marine engineer, I can tell you that the biofouling problem is far from solved. To date, copper biocide works best, but is terrible for the environment. A lot of the new coatings are also 'speed-release', meaning the hull must travel a certain speed in the water before the biofouling simply falls off. Obviously for a hull that site stagnant in the water, like Natick, this type of coating won't help. Many people have tried to solve the issue passivly, and even tried mimicking shark skin (tiny chevron-shaped scales) at the microscale to minimized biological growth's ability to "latch" to the material surface. However, I haven't seen any good commercially viable progress in practice. I'm not sure how the MS Natick's cooling system works, but if it's anything like a ship, the heat transfer surface is NOT typically the skin of the hull (although keel coolers are essentially that, but I don't see keel coolers on the Natick hull). Instead, ship cooling systems typically suck in the virtually endless supply of cold seawater, run it through a heat exchanger (often a plate type), generally with a feshwater loop on the other side that runs to hardware to be cooled. The servers would be cooled by this fresh chillwater loop. The above system only works if a.) you have much excess cool seawater than heat infusion (i.e. you're not trying to cool a large server farm in a stationary pond or small lake), and b.) You have means to clean the biofouling that will occur on the seawater side of the heat exchanger if left unabated. The latter, as indicated by reduced cooling capacity, may be why MS needed to stop the project 3 years shy of the objective completion date.