Les Dobbe
"Voyager" Selene5334

Phil, Bill is spot on with pricing. One of the factors I went with Keypower was total system integration. At the time they offered the get home drive, stabilizers, a hydraulic alternator, hydraulic thrusters and a hydraulic bilge pump. I wanted to try and alleviate cross brands coordinating the hydraulic design and who would take the lead. I ended up with one manufacturer who took total ownership. Regarding trans run times. Twin Disc told me, officially, to run 8 hours and to fill the trans full of oil then drain to a full level. Unofficially they said given the slow RPM they said it would go a "long" time. I have a reverso system for a lot of applications so I thought I could easily fill and drain while underway if I were inclined to. Downsides: Marginal speed/power for a long term solution. My system was designed to go indefinitely. Advantages: Little additional system maintenance. I delivered, 3000 miles, another boat with a wing engine and found that the yaw in the boat, with an offset wing engine, was more than the autopilot could overcome. This was a deciding factor for me in my order process. Other owners of the same brand size did not experience the same effect. This discussion has come up several times to the list but I am very happy with my solution and have had no regrets. * I have a hard enough time keeping up with cleaning my bottom and thrusters in the tropics let alone another prop to take care of. Les Dobbe "Voyager" Selene5334 > > Those of you who are driving the main shaft using a hydraulic motor: > What are the down sides to pushing the main shaft with the > transmission in neutral? Can this be done indefinitely without > damage? Is there a ball park cost figure for adding one of these > clamp-on drive units? > > Phil Eslinger > Flat Earth N50 > > > > We have a Twin Disc transmission that will run for several days in neutral > without a problem. That said, we have installed a trailing pump that > circulates the transmission oil while the get home drive is engaged. This > allows continuous operation. > > The complete drive installation was in excess of $30,000.00+ because we had an > early model from a previous manufacturer that subsequently sold the rights to > Wesmar. We had to do a lot of extra machining and hydraulic work to make the > drive engagement operational from a remote location and we also machined new > NiAl Bronze engagement cog rings to replace the Aluminum cogs that came with > the unit. I am not sure, but I think you can install the new improved drive > from Wesmar for $20,000 or less depending on the size of the unit. Les Dobbe > stated that Keypower has eliminated the need for cutting the main shaft (the > main reason we did not go with Keypower) and that makes the Keypower unit a > good option too in my opinion. I am not completely sure, but I think both the > Keypower and Wesmar units are priced similarly. > > Bill Bahlburg > Porosity Selene5903

The "official" and "unofficial" comments from Twin Disc on free- wheeling the main shaft while a wing engine powers the boat (or driving shaft via a hydraulic engine) when the main is down are the same as I got from ZF relative to their transmissions. Basically, top up the oil and it should be OK. ZF's big caution was not to forget that you'd overfilled the oil when you were able to restart the main. Apparently powering the tranny via main while it has a gross oil overfill causes problems. As far as yaw from the wing engine, we have found that to be of little consequence when underway. In fact, we use the wing all the time as a trolling engine, running at about 2 knots. Whether trolling or using it to cruise boat at 5 knot range, it takes about 8-10 degrees of rudder to compensate for yaw. I've given my autopilot 20 degrees of authority, and would give it more if I was running in significant seas using the wing engine. Default rudder authority on many autopilot installations is about 12 degrees, which would have resulted in the issue that Les spoke of. But that's an easy problem to tweak away. My wing engine is a 70hp and it runs my boat at 5+ knots in flat water. That's about the minimum for my size boat (130,000 pounds). One of the big advantages of a wing with separate shaft is that you can foul a main prop and/or damage the wheel, not to mention suffering a catastrophic transmission failure that could force you to lash main shaft immobile. On my boat, the folding wing prop is located quite a ways forward of the main, so a tangled, trailing line is unlikely to foul it as long as I'm going forward. Also, since the prop folds, it has a better chance of releasing a line or extensive bull kelp that did get around it. I would hazard a guess that many more boats lose their mains temporarily due to fouling than due to engine failure, and there are conditions where going into the water to cut away line isn't an option (night, heavy weather, etc.). At the minimum, the wing prop lets you maintain control of the boat and hold a comfortable position relative to the waves until you can get into the water and free main-- or get help to do it. Also, when we are entering truly hairy waters (tidal rapids, etc) with the rocks very close, I sometimes have the wing running and warmed up and ready to give me steerageway if something happened to the main. Otherwise, you could be on the rocks in a couple of minutes. And with the offset position, it also gives you a measure of "twin engine" turning ability if something happened to rudder. In other words, between forward and reverse, you could put that "yaw" issue to work for you. So as you can tell, I'm a big fan of offset wing engines with "sacred" separate fuel supplies, batteries, shaft, prop, etc. and the flexibility that comes with all that. Some owners add additional alternators and hydraulic pumps to wing as well, given we might as well put that little diesel (mine is a Lugger, so its built to be used) to work. John Marshall N5520-Serendipity On Sep 13, 2009, at 8:49 AM, Les Dobbe wrote: > Phil, > Bill is spot on with pricing. One of the factors I went with > Keypower was total system integration. > At the time they offered the get home drive, stabilizers, a > hydraulic alternator, hydraulic thrusters and a hydraulic bilge pump. > I wanted to try and alleviate cross brands coordinating the > hydraulic design and who would take the lead. I ended up with one > manufacturer who took total ownership. > Regarding trans run times. Twin Disc told me, officially, to run > 8 hours and to fill the trans full of oil then drain to a full > level. Unofficially they said given the slow RPM they said it would > go a "long" time. > I have a reverso system for a lot of applications so I thought I > could easily fill and drain while underway if I were inclined to. > Downsides: Marginal speed/power for a long term solution. My > system was designed to go indefinitely. Advantages: Little > additional system maintenance. I delivered, 3000 miles, another > boat with a wing engine and found that the yaw in the boat, with an > offset wing engine, was more than the autopilot could overcome. This > was a deciding factor for me in my order process. Other owners of > the same brand size did not experience the same effect. > This discussion has come up several times to the list but I am > very happy with my solution and have had no regrets. > * I have a hard enough time keeping up with cleaning my bottom and > thrusters in the tropics let alone another prop to take care of. > Les Dobbe > "Voyager" Selene5334 >> >> Those of you who are driving the main shaft using a hydraulic >> motor: What are the down sides to pushing the main shaft with >> the transmission in neutral? Can this be done indefinitely >> without damage? Is there a ball park cost figure for adding one >> of these clamp-on drive units? >> >> Phil Eslinger >> Flat Earth N50 >> >> >> >> We have a Twin Disc transmission that will run for several days in >> neutral >> without a problem. That said, we have installed a trailing pump that >> circulates the transmission oil while the get home drive is >> engaged. This >> allows continuous operation. >> >> The complete drive installation was in excess of $30,000.00+ >> because we had an >> early model from a previous manufacturer that subsequently sold the >> rights to >> Wesmar. We had to do a lot of extra machining and hydraulic work >> to make the >> drive engagement operational from a remote location and we also >> machined new >> NiAl Bronze engagement cog rings to replace the Aluminum cogs that >> came with >> the unit. I am not sure, but I think you can install the new >> improved drive >> from Wesmar for $20,000 or less depending on the size of the unit. >> Les Dobbe >> stated that Keypower has eliminated the need for cutting the main >> shaft (the >> main reason we did not go with Keypower) and that makes the >> Keypower unit a >> good option too in my opinion. I am not completely sure, but I >> think both the >> Keypower and Wesmar units are priced similarly. >> >> Bill Bahlburg >> Porosity Selene5903 > _______________________________________________ > http://lists.samurai.com/mailman/listinfo/passagemaking-under-power > > To unsubscribe send email to > passagemaking-under-power-request@lists.samurai.com with the word > UNSUBSCRIBE and nothing else in the subject or body of the message. > > Passagemaking Under Power and PUP are trademarks of Water World > Productions, formerly known as Trawler World Productions.