Thank you both for the insight. Yes, I do now recall the dual boat tether concept and I have some working back ground in towing a long array of gear. From a pilot's point of view, I can see an advantage of the dual boat/tether over the towed array. In that, turning would be easier as well as being able to "lay out" a broader path than a towed array.
The need for a sail boat to tack back and forth into the wind does seem challenging with a tether between the 2 boats. But, I can see how a spring line rigging could adjust for any lag between boats in that type of maneuver. The symmetrical hull concept is interesting in that I have never considered a sail boat being able to "immediately" reverse direction. I personally would like to play with the idea of modifying the bright water injectors along the tether to act as a "bow truster" type of directional control for the tether. That may help in overall control of the configuration. The recommended bubble diameter is .002mm. I can only see ultrasound providing that type size for a high throughput operation. I believe a table top experiment can possibly be done using the parts from an off the self ultrasonic humidifier and deep well pump. Measuring such small bubbles is something I have not studied yet. I did read in the paper Dr. Caldeira offered of observations of long lived bubbles through possible contamination of a natural surfactant film. Yet, I don't think the nature of the surfactant was mentioned. I refer to the first page 2nd section https://docs.google.com/viewer?a=v&pid=forums&srcid=MDE0NTY3NTk0NzY2MTMxMzQ4MjEBMDA1OTY0NDQ3MDgzNzU0NTIwODkBQkFOTGtUaWtZQ0pLSmJ2UzFRdFAzbmFrTHZkUTl3ay1kd0FAbWFpbC5nbWFpbC5jb20BNAE&pli=1 Well, again, thank you both for the feed back. I will spend more time thinking about this. On Wed, Apr 27, 2011 at 5:29 AM, Andrew Lockley <and...@andrewlockley.com>wrote: > Stephen, > > This technology is already used for towing hydrophone streamers in geophys, > but it doesn't work quite like you suggest. There's no need for two boats, > and instead there's a paid of towed hydrofoils behind one boat, with the > support line tensioned between them. The low mass of the hydrofoils means > that there's no real shock on the cable in rough seas. The bubble > generators would be strung out on streamers behind this towed line. > > The bubbles would be distributed by a number of 'birds' which are depth-set > from the control room - just like the hydrophones are currently. > > To get good saturation with bubbles, I suggest that they'd need to be > delivered at a variety of depths - but whether that's worth doing depends of > course on the lifetime. No use dropping them ten metres down if they don't > last long enough to mix or rise. > > A > > > On 27 April 2011 13:05, Stephen Salter <s.sal...@ed.ac.uk> wrote: > >> Hi All >> >> Michael Hayes asks about how bubbles could be deployed. >> >> One possibility would be for a pair of wind-driven vessels to sail side by >> side at, say, a kilometre separation, attached to each other by a buoyant, >> streamlined tether. >> >> The chord of the tether would be about 100 mm. In plan it would form a >> catenary with a generous bulge to reduce the tensile load. The nose of >> tether would contain a strong Kevlar or carbon tension member. Behind this >> would be a number of high-pressure air-lines taking very well filtered air >> from each vessel to a porous strip near the nose of the foil section and >> running the full length. The drag of the tether would be reduced by the >> bubble layer on the underside. >> >> The tether would have to be elastic enough to follow the curvature of the >> wave slope. In most sea states this is surprisingly low but elasticity can >> be increased by running the tensile member in a series of S shapes. >> >> The vessels need power but could generate this in the same way as >> suggested for the cloud albedo project. Indeed it would not be difficult to >> design a dual purpose vessel which would change mode according to cloud >> conditions. It would be convenient if the vessels were symmetrical fore and >> aft so that they could tack by going into reverse. >> >> The design does need information on bubble life and the best bubble >> diameter and I would be most grateful for any advice on this matter. >> >> Michael mentions the Dracone project. I worked on this in a very junior >> capacity in 1960 but a kilometre wide bubble wake would be cheaper if the >> bubbles can last long enough and less of a risk than a Dracone that got >> loose. >> >> Stephen >> >> Emeritus Professor of Engineering Design >> Institute for Energy Systems >> School of Engineering >> Mayfield Road >> University of Edinburgh EH9 3JL >> Scotland >> Tel +44 131 650 5704 >> Mobile 07795 203 195 >> www.see.ed.ac.uk/~shs >> >> >> >> On 26/04/2011 23:21, Michael Hayes wrote: >> >>> Please help me understand the mechanics of Bright Water deployment. I >>> have spent many months living on the Bering Sea (in winter) and have piloted >>> 150ft fishing vessels in that area for countless hours. I have watched the >>> sea continually produce white caps for as far as I could see for days and >>> weeks at a time. How can a practical, cost effective and meaningful use of >>> bright water be deployed which comes even close to .0001 percent of the >>> natural production of white caps? The energy and equipment needed to cover >>> any meaningful amount of the sea is difficult for me to comprehend. >>> Outfitting fishing fleets with the needed equipment and paying the boat >>> owners to run the gear is possible. But, we are only talking about a bright >>> water wake which lasts for only a short distance...at best. >>> >>> Designing autonomous platforms specifically for the mission may be >>> possible, but, one storm could beach every single platform within a few >>> hours. Who and how will they be collected and sent back out? This, from a >>> seaman's point of view, is difficult to see as being practical. I have >>> studied the concept though what has been offered here and through other >>> links. The mechanical challenge of producing such small bubbles is >>> interesting and I have even spent time thinking through the possible use >>> high throughput ultrasonic injectors. But, I still come back to the >>> questions of; 1) how can bright water be practically deployed? 2) How can >>> the investment be justified when the wide area effect is so tenuous? 3) >>> Would not reflective large surface rafts provide a more cost effective long >>> term overall result? >>> >>> There is the option of a reflective form of the Dracone Barge as a useful >>> way to deploy large area ocean surface SRM. " >>> http://en.wikipedia.org/wiki/Dracone_barge. >>> >>> If such barges were deployed in large numbers a large area rafting system >>> could be secured in needed areas and moved as the season changes. With small >>> desalinization pods attached, we could have not just have low cost/long >>> term/flexible ocean surface SRM but a nice supply of needed fresh water. >>> Sell the fresh water and buy more bags!!!! >>> >>> I ask your help in understanding how bright water can be a competitive >>> form of SRM. >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "geoengineering" group. >>> To post to this group, send email to geoengineering@googlegroups.com. >>> To unsubscribe from this group, send email to >>> geoengineering+unsubscr...@googlegroups.com. >>> For more options, visit this group at >>> http://groups.google.com/group/geoengineering?hl=en. >>> >> >> -- >> The University of Edinburgh is a charitable body, registered in >> Scotland, with registration number SC005336. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "geoengineering" group. >> To post to this group, send email to geoengineering@googlegroups.com. >> To unsubscribe from this group, send email to >> geoengineering+unsubscr...@googlegroups.com. >> For more options, visit this group at >> http://groups.google.com/group/geoengineering?hl=en. >> >> > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to geoengineering@googlegroups.com. > To unsubscribe from this group, send email to > geoengineering+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > -- *Michael Hayes* *360-708-4976* http://www.wix.com/voglerlake/vogler-lake-web-site -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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