Greetings all, just a quick note to let you know we arrived safely in PLC, Venezuela on Thursday AM logging 616.5 nm which included about 30 during our sea trials. We made one stop in St Martin for supplies. Fuel used was 433 gals and the genset was running 90% of the time (200 hrs) for our air conditioning. Also the main engine alternator was not hooked up yet so the genset was our sole source of AC and DC. We had two issues on the trip: 1. Lost the dinghy when the tow line parted. Found it and replaced the tow line with a new one and had no further problems in the 600 miles. 2. A fitting on the steering ram bypass valve failed and dumped all the hydraulic fluid. A bit tricky putting in a hose to bypass the bypass and then filling and bleeding the system while beam-to in 8-10' seas but doable thanks to the roll tank which stabilizes Swan Song. I guess we can take the cover off the top of our pilothouse now and let everyone see why Swan Song doesn't roll. We have a tank engineered with baffles that keep 200 gals of water 180 degrees out of sync with the roll period of the boat. The net result is that Swan Song doesn't roll enough to notice whether moving, at the dock or at anchor. When other boats a rolling and bobbing about she just sits there. Amazing! It does nothing for pitch so we still go up and down but very, very little roll. The tank is 12 ft long, 4' wide and 16" high and is firmly attached to the boat. Roughly 1500 lbs of water sloshing back and forth out of sync with the boat. We have a solid state gyro with a DAC which feeds our laptop. Prior to filling the tank you could get Swan Song rolling at the dock 10-15 degrees by synchronously stepping on the side. You can do this with most boats. Some will roll more some will roll less but all will roll..even a catamaran. After filling the tank you can't even get the rolling to start! Timing 10 of these rolls will give you the roll period of you boat. In Swan Song's case it was 4.1 seconds per roll. This goes into the formula that helps define the tank. The second item is the stiffness of the vessel. For this you need to do an inclination test. Putting weights on one side then the other and accurately measuring the heel angle in calm water. In Swan Song's case we got 500 lbs per degree to about 5 degrees and then it goes to 600 lb/degree and is 1000 lb/degree at 10 degrees static heel. So 1500 lbs of water on the top of the pilothouse stacked at one end (which is impossible as the tank is only 16" high) would result in a worst case added heel angle of 3 degree. The conclusion is that the boat has plenty of reserve stability for the roll tank. The last part of the input is the hull lines. In our case there were none so we measured the hull at 15 stations in one foot depth increments. From this a wire frame computer model was generated and input into the software. The output is a set of parameters that allow one to design a tank with fixed baffles that will delay the free surface effect of the water such that it becomes an advantage to you vs. a detriment. No power, no pumps, no valves, no maintenance, no drag, no deployment/retrieval effort, no nothing. It just sits up there and works 100% of the time. We expect over time that we will find that adjusting the amount of water in the tank in various wave heights will improve it even more. The trip down was 350 miles of beam sea ranging from 5 to 12' and except for the occasional "drop thru a wave" we were very comfortable. With an eye height of 12' in our seat looking out the Port side window and up at the wave tops on occasion did get that knee jerk reaction but it never was required. Our new Fly By Wire system performed flawlessly. We have zero mechanical controls...no steering nor engine controls. Interesting it was the steering ram bypass valve that failed. If we' had a conventional system and lost all the hydraulic fluid I doubt we could have repaired it at sea in 2 hours if at all. A great trip down, the Marina folks are great and the officials are very polite. There is a very visible show of various law enforcement people. Sort of like the local police, the state police, the harbor patrol, the coast guard and the Navy all keeping an eye on a parade in Boston Harbor. Is there crime here? Is there crime in New York? You better believe it. Same thing. More reports, etc. as we get settled in. My work list is ten pages long and the "honey do" list is even longer. Sure hope the hurricane season ends quickly so I can get out of the marina ;-) Dave & Nancy Swan Song 1974 Roughwater 58 Caribbean Tour 2006

Very interesting post. I've never heard of the stability tank. How would I get ahold of the software to design one or have one designed for me? Also, this would be an interesting post on the T&T website. Carl Martin Scout 30 Hudson Beach, FL ----- Original Message ----- From: "Dave Cooper" <swansong@gmn-usa.com> To: "'Passagemaking Under Power List'" <passagemaking-under-power@lists.samurai.com> Sent: Tuesday, August 29, 2006 9:13 PM Subject: [PUP] FW: Swan Song in Venezuela > Greetings all, just a quick note to let you know we arrived safely in PLC, > Venezuela on Thursday AM logging 616.5 nm which included about 30 during > our > sea trials. We made one stop in St Martin for supplies. > > Fuel used was 433 gals and the genset was running 90% of the time (200 > hrs) > for our air conditioning. Also the main engine alternator was not hooked > up > yet so the genset was our sole source of AC and DC. > > We had two issues on the trip: > 1. Lost the dinghy when the tow line parted. Found it and replaced the tow > line with a new one and had no further problems in the 600 miles. > 2. A fitting on the steering ram bypass valve failed and dumped all the > hydraulic fluid. A bit tricky putting in a hose to bypass the bypass and > then filling and bleeding the system while beam-to in 8-10' seas but > doable > thanks to the roll tank which stabilizes Swan Song. > > I guess we can take the cover off the top of our pilothouse now and let > everyone see why Swan Song doesn't roll. > We have a tank engineered with baffles that keep 200 gals of water 180 > degrees out of sync with the roll period of the boat. The net result is > that > Swan Song doesn't roll enough to notice whether moving, at the dock or at > anchor. When other boats a rolling and bobbing about she just sits there. > Amazing! > It does nothing for pitch so we still go up and down but very, very little > roll. > The tank is 12 ft long, 4' wide and 16" high and is firmly attached to the > boat. Roughly 1500 lbs of water sloshing back and forth out of sync with > the > boat. > > We have a solid state gyro with a DAC which feeds our laptop. Prior to > filling the tank you could get Swan Song rolling at the dock 10-15 degrees > by synchronously stepping on the side. You can do this with most boats. > Some > will roll more some will roll less but all will roll..even a catamaran. > After filling the tank you can't even get the rolling to start! > > Timing 10 of these rolls will give you the roll period of you boat. In > Swan > Song's case it was 4.1 seconds per roll. This goes into the formula that > helps define the tank. > > The second item is the stiffness of the vessel. For this you need to do an > inclination test. Putting weights on one side then the other and > accurately > measuring the heel angle in calm water. In Swan Song's case we got 500 lbs > per degree to about 5 degrees and then it goes to 600 lb/degree and is > 1000 > lb/degree at 10 degrees static heel. > > So 1500 lbs of water on the top of the pilothouse stacked at one end > (which > is impossible as the tank is only 16" high) would result in a worst case > added heel angle of 3 degree. The conclusion is that the boat has plenty > of > reserve stability for the roll tank. > > The last part of the input is the hull lines. In our case there were none > so > we measured the hull at 15 stations in one foot depth increments. From > this > a wire frame computer model was generated and input into the software. > > The output is a set of parameters that allow one to design a tank with > fixed > baffles that will delay the free surface effect of the water such that it > becomes an advantage to you vs. a detriment. No power, no pumps, no > valves, > no maintenance, no drag, no deployment/retrieval effort, no nothing. It > just > sits up there and works 100% of the time. > > We expect over time that we will find that adjusting the amount of water > in > the tank in various wave heights will improve it even more. The trip down > was 350 miles of beam sea ranging from 5 to 12' and except for the > occasional "drop thru a wave" we were very comfortable. With an eye height > of 12' in our seat looking out the Port side window and up at the wave > tops > on occasion did get that knee jerk reaction but it never was required. > > Our new Fly By Wire system performed flawlessly. We have zero mechanical > controls...no steering nor engine controls. Interesting it was the > steering > ram bypass valve that failed. If we' had a conventional system and lost > all > the hydraulic fluid I doubt we could have repaired it at sea in 2 hours if > at all. > > A great trip down, the Marina folks are great and the officials are very > polite. There is a very visible show of various law enforcement people. > Sort > of like the local police, the state police, the harbor patrol, the coast > guard and the Navy all keeping an eye on a parade in Boston Harbor. > > Is there crime here? Is there crime in New York? You better believe it. > Same > thing. > > More reports, etc. as we get settled in. My work list is ten pages long > and > the "honey do" list is even longer. Sure hope the hurricane season ends > quickly so I can get out of the marina ;-) > > Dave & Nancy > Swan Song > 1974 Roughwater 58 > Caribbean Tour 2006 > _______________________________________________ > Passagemaking-Under-Power Mailing List

At 09:08 AM 8/30/2006, you wrote: >Very interesting post. I've never heard of the stability tank. How would I >get ahold of the software to design one or have one designed for me? This is, I think, a job for a professional, as poorly designed roll tanks can easily decrease stability. Michael Kasten has a discussion of roll--reduction strategies here: http://www.kastenmarine.com/roll_attenuation.htm Best, Steve Steve Dubnoff 1966 Willard Pilothouse www.mvnereid.com sdubnoff@circlesys.com

Thanx for the info. Happy Cruising, Carl ----- Original Message ----- From: "Steven Dubnoff" <sdubnoff@circlesys.com> To: "Passagemaking Under Power List" <passagemaking-under-power@lists.samurai.com> Sent: Wednesday, August 30, 2006 3:15 PM Subject: Re: [PUP] FW: Swan Song in Venezuela > At 09:08 AM 8/30/2006, you wrote: >>Very interesting post. I've never heard of the stability tank. How would >>I >>get ahold of the software to design one or have one designed for me? > > This is, I think, a job for a professional, as poorly designed roll > tanks can easily decrease stability. Michael Kasten has a > discussion of roll--reduction strategies here: > > http://www.kastenmarine.com/roll_attenuation.htm > > Best, > > Steve > > > > Steve Dubnoff > 1966 Willard Pilothouse > www.mvnereid.com > sdubnoff@circlesys.com > _______________________________________________ > Passagemaking-Under-Power Mailing List