<Bob: I really enjoyed your post and look forward to looking at your website when you get it up. I am a former sailor (Niagara 42') with numerous ocean passages, and I am now researching a Trawler design in the 40' size range. I have spoken to a few naval architects about a design - my requirements are for a draft < 5' and bridge clearance < 11' because I want to take the boat to Amsterdam and cruise up the Rhine to the Danube and down to the Black Sea. Rolling is an issue which concerned me and I dislike the paravane idea because it is cumbersome, expensive and possibly dangerous. It also adds lots of sailboat like gear which would have to be carried on deck in the canals - a situation I wish to avoid. Hence my interest in your stabilising tank. Based on your research to date do you think it is possible to achieve in a 40' trawler design? Regards Ed Quigley Ed, When designing a boat from scratch it will be easy to build a tank into the boat. The new San Francisco pilot vessels have a tank built in under the pilothouse and it would be simple to build one into the roof over the salon or into the forward fairing of the flybridge of a custom built boat. Don is also looking at utilizing a radar arch as in making the arch thicker and longer fore and aft and inter connecting the two sides with valved piping. It doesn't have to be one tank and could be two three or four smaller tanks placed in different locations. I am now using saltwater but for long trips will replace with fresh to have an emergency backup. One of our goals is to better quantify what is an acceptable roll reduction and be able to offer several different levels of efficiency. If a vessel is never going to leave the intracoastal or bays like the Chesapeake she probably doesn't need the same degree of reduction as a boat fishing the North Atlantic. I know from experience that with my tank at its full mark the action is too efficient when at the dock. She starts to roll and very abruptly stops after only two or three degrees. If I empty a quarter of the fluid I can smooth out the action so she rolls to four or five degrees and stops rolling more gently. While I didn't plump a pump to the tank in the beginning I am going to do so shortly, probably utilizing the low pressure feed pump for my watermaker, so I can vary the amount of fluid to better tune the tank for different conditions. The fishing vessels have to have large drains and a pump as they are required by Fisheries to be able to dump the tank in under four minutes. Their tanks are steel and while they have sight tubes they all just time the pump to gauge how full. Obviously, to be able to dump the tank you have to have large vents which, if not carefully placed as in if too far out from center, can spill fluid when its rough. One fishing boat skipper whose vent was not properly placed decided he would get ahead of the curve and start out with his tank overfilled, in this case right to the top instead of one third filled, and couldn't understand why his boat was behaving funny. Education, it never ends. Bob Phillips