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Bryce Grefe
Power thruster
I just put one on my Nissan 5HP this spring, and I'd estimate its claims are in-line. Bryce S/V Spellbinder H410
I just put one on my Nissan 5HP this spring, and I'd estimate its claims are in-line. Bryce S/V Spellbinder H410
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Walt Remele
Ducted fan
Bought our H26 in 1994 w/ a 4 stroke Yamaha 9.9 for power. Did well underway until any kind of a seaway developed. Six years ago I installed a thruster mfg'd in Canada. Power Thruster I believe is the name but would have to look it up to be specific. Their claim was a 30 percent increase in bollard pull. 70 lbs increased to 110 pounds. It was very easy to install, definitely increased the amount of effort required to pull the motor up, and certainly moved the boat easier. It was not cheap, somethig around $600 if I rememeber correctly. Was it worth it? Definitely! Cruising at the same speed of 5.5 kts is now accomplished at a lower RPM, increasing cruising distance. Hull speed is reached at less than full throttle and I can keep the cruise speed far longer as the winds and waves build. The installatin makes a lot of sense for a low speed application. Turns the prop into a ducted fan, regaing a lot of lost effort off of the prop tips. If anyone would like specifics I can look up the info when I get back from work next week. Fair winds! Walt J Shammah
Bought our H26 in 1994 w/ a 4 stroke Yamaha 9.9 for power. Did well underway until any kind of a seaway developed. Six years ago I installed a thruster mfg'd in Canada. Power Thruster I believe is the name but would have to look it up to be specific. Their claim was a 30 percent increase in bollard pull. 70 lbs increased to 110 pounds. It was very easy to install, definitely increased the amount of effort required to pull the motor up, and certainly moved the boat easier. It was not cheap, somethig around $600 if I rememeber correctly. Was it worth it? Definitely! Cruising at the same speed of 5.5 kts is now accomplished at a lower RPM, increasing cruising distance. Hull speed is reached at less than full throttle and I can keep the cruise speed far longer as the winds and waves build. The installatin makes a lot of sense for a low speed application. Turns the prop into a ducted fan, regaing a lot of lost effort off of the prop tips. If anyone would like specifics I can look up the info when I get back from work next week. Fair winds! Walt J Shammah
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Rick Webb
I was Wondering
If a piece of like 10" PVC pipe over the prop would do anything more than protect the prop. I had a section but threw it away when we moved last time.
If a piece of like 10" PVC pipe over the prop would do anything more than protect the prop. I had a section but threw it away when we moved last time.
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Tom
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Brad
hey Walt
Hi Walt if it's not too much trouble would you mind looking up the information. It's not a problem if you can't either. Thanks, Brad
Hi Walt if it's not too much trouble would you mind looking up the information. It's not a problem if you can't either. Thanks, Brad
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Walt Remele
Brad
Brad, I'm rotating south for a week off on Tuesday, 8-5. I'll look up all the pertinent info when I get home and post it under this thread. Walt J Shammah
Brad, I'm rotating south for a week off on Tuesday, 8-5. I'll look up all the pertinent info when I get home and post it under this thread. Walt J Shammah
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Brad
10-inch PVC?? Hmmm....
I see discarded cut-off pieces of large diameter PVC pipe laying around consruction jobs often enough to where this might be worth investigationg. However, I've already lost a lot of sailng time this year due to tinkering around, so I don't know if I should take on a new project. Maybe if I stash a piece of the pipe in my garage till late next spring.... Peter H23 "Raven"
I see discarded cut-off pieces of large diameter PVC pipe laying around consruction jobs often enough to where this might be worth investigationg. However, I've already lost a lot of sailng time this year due to tinkering around, so I don't know if I should take on a new project. Maybe if I stash a piece of the pipe in my garage till late next spring.... Peter H23 "Raven"
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Tom Wootton
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Rick Webb
Keep us Updated Peter
I figured if nothing else it would keep the prop free from the rudder, the bottom, and from lines on crab pots, anchors, whatever and for somthing that would be virtually free.
I figured if nothing else it would keep the prop free from the rudder, the bottom, and from lines on crab pots, anchors, whatever and for somthing that would be virtually free.
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Rick Webb
Another Idea
I was looking at the picture of the Power Thruster and it looked as though someone with a Dremel Tool and a piece of the afore mentioned discarded scrap of 10" PVC pipe could create something very similar for free. I am going to keep my eyes open for a piece and I'll report back on any success.
I was looking at the picture of the Power Thruster and it looked as though someone with a Dremel Tool and a piece of the afore mentioned discarded scrap of 10" PVC pipe could create something very similar for free. I am going to keep my eyes open for a piece and I'll report back on any success.
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Ray Trombino
Power Thruster
I put a power thruster on my Honda 9.9, and while I can't speak to more power, I do throw less of a "wake", and I don't cavitate on turns. Overall, it was worth the investment. I would think twice before using the PVC. If it cracked and got into the prop, that would be a mess with flying plastic everywhere. Power Thruster is stainless steel, and well made.
I put a power thruster on my Honda 9.9, and while I can't speak to more power, I do throw less of a "wake", and I don't cavitate on turns. Overall, it was worth the investment. I would think twice before using the PVC. If it cracked and got into the prop, that would be a mess with flying plastic everywhere. Power Thruster is stainless steel, and well made.
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Walt Remele
Handler
South of 70 N for a week and amazed myself by finding what I was looking for amidst all the boxes generated by moving from the old house to the new house. Handler is the name of the thruster I installed on our H26 in 1999. It is a true Kort nozzle. Mfg'd by Port Kent Marine Inc. PB 311 Port Kent, NY 12975-0311 Tel: 514 637-2566 Did a search on the web and only came up with a mention of the above address. No link. For those that are interested hopefully they are still in business. While the installation certainly adds weight to the bottom of the motor the gain in thrust generated by a fully enclosed prop far outweighs the extra effort to raise the motor. Walt J Shammah
South of 70 N for a week and amazed myself by finding what I was looking for amidst all the boxes generated by moving from the old house to the new house. Handler is the name of the thruster I installed on our H26 in 1999. It is a true Kort nozzle. Mfg'd by Port Kent Marine Inc. PB 311 Port Kent, NY 12975-0311 Tel: 514 637-2566 Did a search on the web and only came up with a mention of the above address. No link. For those that are interested hopefully they are still in business. While the installation certainly adds weight to the bottom of the motor the gain in thrust generated by a fully enclosed prop far outweighs the extra effort to raise the motor. Walt J Shammah
10-inch PVC pipe
Ten-inch PVC pipe has a wall thickness about 1/4-inch, and it's strong enough to be buried tens of feet below the ground surface without collapsing. I doubt strongly it would crack. Even the pipe did crack and get into the prop, pieces won't be flying because everything would be underwater. The drawback with PVC pipe is that it's susceptible to UV damage from the sun (like most plastics). It probably wouldn't last more than a year or two. However at that price (free) you could afford to replace it every year. Damn...now I'll HAVE to go make one just to satisfy my curiosity. Peter H23 "Raven"
Ten-inch PVC pipe has a wall thickness about 1/4-inch, and it's strong enough to be buried tens of feet below the ground surface without collapsing. I doubt strongly it would crack. Even the pipe did crack and get into the prop, pieces won't be flying because everything would be underwater. The drawback with PVC pipe is that it's susceptible to UV damage from the sun (like most plastics). It probably wouldn't last more than a year or two. However at that price (free) you could afford to replace it every year. Damn...now I'll HAVE to go make one just to satisfy my curiosity. Peter H23 "Raven"
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Chuck
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Paul H
Kort Nozzle
If I'm looking at the diagram correctly the configuration they are suggesting is the Marin #37. The schematic shows sides that are shaped like aircraft wings to give it an aerodynamic flow. Since the fluids(or air) passing over these surfaces has to travel faster,this is where your increase in velocity would come from. Am I correct on this? If so just putting in pvc pipe won't do it unless the sides were shaped. You may gain some efficiency but not as much as you would if it had the right shape. Paul H S/V Linda Belle 95 H26
If I'm looking at the diagram correctly the configuration they are suggesting is the Marin #37. The schematic shows sides that are shaped like aircraft wings to give it an aerodynamic flow. Since the fluids(or air) passing over these surfaces has to travel faster,this is where your increase in velocity would come from. Am I correct on this? If so just putting in pvc pipe won't do it unless the sides were shaped. You may gain some efficiency but not as much as you would if it had the right shape. Paul H S/V Linda Belle 95 H26
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Nils Anderson
PVC may be weak at the attach points
Very interesting discussion. Thanks for the link on the Kort Nozzle. I think anything you add to shroud the prop will give positive results because you are basically redirecting the lost radial flow horizontally for usefull work. The one offset to this is the drag created by the cylinder. Is PVC strong enough to hold on to its bolt attachments while draging thru the water at 5 knots on the outside and maybe 15 knots on the inside? Another question is how long should the nozzle be? My prop has a 12 inch diameter (Yamaha 9.9 4-stroke high thrust) so I was thinking a 12 inch length. Obviously the longer the better flow, but more drag. The key is strong attach points (plural). If it works, we all should do it.
Very interesting discussion. Thanks for the link on the Kort Nozzle. I think anything you add to shroud the prop will give positive results because you are basically redirecting the lost radial flow horizontally for usefull work. The one offset to this is the drag created by the cylinder. Is PVC strong enough to hold on to its bolt attachments while draging thru the water at 5 knots on the outside and maybe 15 knots on the inside? Another question is how long should the nozzle be? My prop has a 12 inch diameter (Yamaha 9.9 4-stroke high thrust) so I was thinking a 12 inch length. Obviously the longer the better flow, but more drag. The key is strong attach points (plural). If it works, we all should do it.
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Rick Webb
One Potential Downfall
In reverse the exhaust may cause cavitation if it exhausts through the prop. Again, for the price it is worth a try. Maybe cutting pieces that look like the ones one the Power Thruster would solve that issue. As for the UV, why can't they just be painted? I am eager to try it out or to hear the testimonial of one who has.
In reverse the exhaust may cause cavitation if it exhausts through the prop. Again, for the price it is worth a try. Maybe cutting pieces that look like the ones one the Power Thruster would solve that issue. As for the UV, why can't they just be painted? I am eager to try it out or to hear the testimonial of one who has.
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