bryce
Crew Member
I am really really curious
Toroidal propellers: gas burn reduction potential?
- Thread starter pescador
- Start date
ship happens
Crew Member
Yup. Let's split hairs I got a coin to toss. And unbiased total comparison send off. Well see. Only way
ship happens
Crew Member
These guys don't have a contact page.
gvh
Member
You need to send a request by email requesting what time they can call you back to discuss. I didn’t find the individual to be a “salesman” but his specific experience was limited. Next step is to send in data and $100 per engine and their Engineers will respond with a recommendation. My boat is pretty popular out there and I was hoping to get information based on actual performance tests. I would think they would have that on most larger glass boats.
I‘ll remain on the fence for now.
I‘ll remain on the fence for now.
Sharphooks
Well-Known Member
I talked to one of my bait customers this morning who mentioned he’s been running Sharrow props on his rec boat now for a year. Unfortunately, he was in a crappy cellular spot and I lost the connection but before I lost him I asked about their overall performance and whether they were “worth it”—- he did mention he’d had a “pile of fuel costs saved” due to those props.
He was Also on that Duckworth with the twin Yamaha 300’s that BoatTest ran those props on so I’ll ask him about the believability of those charts that were posted and also what brand props were those “traditional” 15.5 x 17’s mounted on those F300’s that the Sharrow’s replaced to come up with those test numbers
He said he’d call back once he’s in range.
And for the guys making noises about the crappy performance of that Duckworth in the 4K range (16 MPH) shown in those charts—-once again, those charts show power curve through the full RPM ladder of the Duckworth’s F300’s with both the traditional props verses the Sharrow props—-with 7-8 guys in that Duckworth, I can imagine you’re not going to see the MPH/RPM numbers you’d see in a similar sized boat with similar power with “traditional” props once it’s out of the hole, on step, then backed off on the throttle to keep the boat at 4K
That’s NOT what those charts are attempting to show —-it’s an apples/oranges attempt to call B.S on the relatively sluggard 16 mph speed for 4K worth of RPM that’s included in those charts ...if they throttled back and ran the boat for 5 minutes at 4K and achieved a top speed of 16 MPH, then yes, a dog probably did use those “traditional” prop flukes as a chewy toy and the Sharrows would nt break a sweat showing a huge improvement
He was Also on that Duckworth with the twin Yamaha 300’s that BoatTest ran those props on so I’ll ask him about the believability of those charts that were posted and also what brand props were those “traditional” 15.5 x 17’s mounted on those F300’s that the Sharrow’s replaced to come up with those test numbers
He said he’d call back once he’s in range.
And for the guys making noises about the crappy performance of that Duckworth in the 4K range (16 MPH) shown in those charts—-once again, those charts show power curve through the full RPM ladder of the Duckworth’s F300’s with both the traditional props verses the Sharrow props—-with 7-8 guys in that Duckworth, I can imagine you’re not going to see the MPH/RPM numbers you’d see in a similar sized boat with similar power with “traditional” props once it’s out of the hole, on step, then backed off on the throttle to keep the boat at 4K
That’s NOT what those charts are attempting to show —-it’s an apples/oranges attempt to call B.S on the relatively sluggard 16 mph speed for 4K worth of RPM that’s included in those charts ...if they throttled back and ran the boat for 5 minutes at 4K and achieved a top speed of 16 MPH, then yes, a dog probably did use those “traditional” prop flukes as a chewy toy and the Sharrows would nt break a sweat showing a huge improvement
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BC Coast Pilot
Well-Known Member
Gear'n'beer!
Well-Known Member
The prototypes were 3D printed. that's how I met the guy.
Dogbreath
Well-Known Member
The Sharrows are So Shiny!
BC Coast Pilot
Well-Known Member
LOL.....new shiny things.....like fishing gear
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kaelc
Crew Member
The moral of the story is buy used, unless interest rates drop and you can get low financing on repowering Merc/Yami's spec or supplied with their efficient props. https://miami.craigslist.org/pbc/boa/d/lake-worth-fountain-33-sport-fish/7587498417.html
kaelc
Crew Member
Eco's in Oak Bay https://www.facebook.com/marketplace/item/1364611200743186/
Sharphooks
Well-Known Member
So I just got off the phone with a guy who was involved in a detailed test of the Sharrows. In exchange for the use of his boat for the test, he was given a pair of Sharrows that he’s been running since last July
I asked him a pile of questions—-First, I wanted to know what the “traditional” props were that were used in the test to compare performance against the Sharrows (they were brand new, out of the box, Yamaha Salt Water Series 15 1/2 x 17P—-the Yamaha engineers on the boat during the test insisted on using brand new props for the baseline. )
He confirmed that the mph to RPM curves you can see in the test results were based on instantaneous power curves, not running steady speeds at different RPM’s... so in reality, that boat with the twin DF300’s would run approx. 30 MPH at 4K with the traditional props, not the 16 MPH you see in the graph.
He confirmed that cruise speed per given RPM (on step, mid range RPM) was significantly increased with the Sharrows compared to the SWS Yamaha props—-they could run at 3.4K and stay on step with 7 guys in the boat with the Sharrows. With the traditional SWS, they had to be in the upper 3K range—-lower RPM per any given cruise speed is where all the fuel savings come from
His ballpark estimate—-20% plus or minus savings in fuel. They burned 4,550 liters last summer (it’s a charter boat). You can work out the amortization schedule of those props based on 20% of that number for a boat that is heavily used like that
The big question is how will they hold up to a wood hit in the water (if you hit one of the props with twins and damage it, be prepared to remove them both)
The other question: what will those delicate flukes look like after a few seasons. I’ve already heard anecdotal stories of PowerTech props breaking flukes just from fatigue——not enough history on how the Sharrows will hold up to draw any conclusions
The noice cancelling—everyone raves about that too...the Sharrows leave a much cleaner wake and engine noise is reduced significantly—-nobody argues that point
I asked him a pile of questions—-First, I wanted to know what the “traditional” props were that were used in the test to compare performance against the Sharrows (they were brand new, out of the box, Yamaha Salt Water Series 15 1/2 x 17P—-the Yamaha engineers on the boat during the test insisted on using brand new props for the baseline. )
He confirmed that the mph to RPM curves you can see in the test results were based on instantaneous power curves, not running steady speeds at different RPM’s... so in reality, that boat with the twin DF300’s would run approx. 30 MPH at 4K with the traditional props, not the 16 MPH you see in the graph.
He confirmed that cruise speed per given RPM (on step, mid range RPM) was significantly increased with the Sharrows compared to the SWS Yamaha props—-they could run at 3.4K and stay on step with 7 guys in the boat with the Sharrows. With the traditional SWS, they had to be in the upper 3K range—-lower RPM per any given cruise speed is where all the fuel savings come from
His ballpark estimate—-20% plus or minus savings in fuel. They burned 4,550 liters last summer (it’s a charter boat). You can work out the amortization schedule of those props based on 20% of that number for a boat that is heavily used like that
The big question is how will they hold up to a wood hit in the water (if you hit one of the props with twins and damage it, be prepared to remove them both)
The other question: what will those delicate flukes look like after a few seasons. I’ve already heard anecdotal stories of PowerTech props breaking flukes just from fatigue——not enough history on how the Sharrows will hold up to draw any conclusions
The noice cancelling—everyone raves about that too...the Sharrows leave a much cleaner wake and engine noise is reduced significantly—-nobody argues that point
ship happens
Crew Member
You say 3400rpm at what MPH? You just said stays on step
Sharphooks
Well-Known Member
Unfortunately he was in the process of launching a boat —-I didn’t want to ask him specific MPH per RPM between the two props. They had 7 people on board during the test. I’m sure that extra weight effected planing speeds per the given RPM with both the traditional SWS and the Sharrows but he did confirm the Sharrows came out of the hole quicker and kept the boat at planing speeds at lower RPM’s
I will try and get specific info —-he mentioned he has all the data and was happy to share it
This link contains enough detail to flesh out some conclusions on how the Duckworth performed with the two different sets of props
Impressive speed on the Sharrows in the mid RPM band.....the SWS edge ahead heading towards WOT
www.sharrowmarine.com
One thing I gathered talking to this guy: there were several Yamaha guys on board during the tests and several Sharrow guys. It was the Yamaha guys who insisted on mounting two brand new traditional SWS props to run against the Sharrows...——they were there to get specific comparison results, not candy coat for Sharrows marketing purposes.
IF you see Yamaha offering outboards with Sharrows in the next 6 month to a year, it’ll be interesting to see what their claims will be with fuel burn and range
I will try and get specific info —-he mentioned he has all the data and was happy to share it
This link contains enough detail to flesh out some conclusions on how the Duckworth performed with the two different sets of props
Impressive speed on the Sharrows in the mid RPM band.....the SWS edge ahead heading towards WOT
Duckworth 30 Offshore XL with Twin Yamaha 300 HP – 99% Faster at 3500 RPM
“If you would have told me that I could bolt something onto my engines and save 20% on fuel while increasing the holeshot, of course, I would not have believed it. If you had told me that this same product would quiet the engine sound down to the point that I no longer had to shut the cabin door...
www.sharrowmarine.com
One thing I gathered talking to this guy: there were several Yamaha guys on board during the tests and several Sharrow guys. It was the Yamaha guys who insisted on mounting two brand new traditional SWS props to run against the Sharrows...——they were there to get specific comparison results, not candy coat for Sharrows marketing purposes.
IF you see Yamaha offering outboards with Sharrows in the next 6 month to a year, it’ll be interesting to see what their claims will be with fuel burn and range
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ship happens
Crew Member
I honestly am sticking to my guns on fuel burn being more important at cruising speed then let's say better hole shot. You spend more time at cruise then getting on plane. 4 grand should be nominally 30 mph. Modern engines can base fuel consumption just from rpm if the boat is powered right and propped right. They know almost exactly the fuel injection constancy, duration, and amount of fuel spray from each duration so right there rpm means how much fuel burned. Unless over propped or underpropped of course then your cruise speed is inefficient
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pescador
Well-Known Member
This is a game changer if it turns out to be true. Transformational change in the marine industry. This is potentially a repeat of 1954 and the jet age just started. It's only a matter of time before the price will drop. My only worry would be getting the right prop. Being on the leading edge, how the hell do you figure out the right prop for your configuration? Traditional props are fairly cheap and if you screw up propping it, you can buy another one and keep the other as a spare. Right now for me the pricing is a 5 year payback. I'd buy one with a 2.5 year payback pricing.
kaelc
Crew Member
It really is a great move by Yamaha when some is spending 75-125k on repowering twins or trips what’s another 10-15k, on you 300-500k boat it’s a great up selling feature better economy and range. I bet they even have a “Tesla” fuel mileage $ savings calculator. I can hear the salesman “your trade in on your old engines covers the cost of the props that are going to “save” you money.”
ship happens
Crew Member
Ok so here is the skinny. I got ahold of Sharrow. The person I spoke with ( nice guy ) couldn't answer technical questions very well. I asked a very simple question.
" so let's say that I have a boat that does 30 mph at 4000 rpm. No issues with this boat as far as current prop type pitch etc. How can I create a 20 to 30 percent fuel efficiency unless I cruise at say 30 mph 3500 rpm ? "
Yes it was a bit of a trick question however the guy was clueless. I spoke with him for a while. I said to him that the modern high HP outboards don't create their HP rating nominally until you hit 5 grand. 4 grand being the most efficient on HP curve and fuel burn. Once you take that RPM down you actually loose HP. At that point like I said before, you can determine fuel burn on RPM, since the modern outboard engines are ECU driven and injected. That being said to gain 20 percent fuel efficiency, you would have to run at about 3000 rpm. Which isn't happening
He said there are no dealers for this product and they will be direct to the customer. 5 grand a prop with a money back guarantee. Each prop is built custom for each boat type and engine type.
I'm sure these props are nice, and I think they might have some advantages, however I can't say that those are worth 5 grand and all the headaches attached. Like sending it back and forth for fitment and or repair as it would be a nightmare to fix.
I personally could not recommend this product as a marine industry professional. I'm out!
" so let's say that I have a boat that does 30 mph at 4000 rpm. No issues with this boat as far as current prop type pitch etc. How can I create a 20 to 30 percent fuel efficiency unless I cruise at say 30 mph 3500 rpm ? "
Yes it was a bit of a trick question however the guy was clueless. I spoke with him for a while. I said to him that the modern high HP outboards don't create their HP rating nominally until you hit 5 grand. 4 grand being the most efficient on HP curve and fuel burn. Once you take that RPM down you actually loose HP. At that point like I said before, you can determine fuel burn on RPM, since the modern outboard engines are ECU driven and injected. That being said to gain 20 percent fuel efficiency, you would have to run at about 3000 rpm. Which isn't happening
He said there are no dealers for this product and they will be direct to the customer. 5 grand a prop with a money back guarantee. Each prop is built custom for each boat type and engine type.
I'm sure these props are nice, and I think they might have some advantages, however I can't say that those are worth 5 grand and all the headaches attached. Like sending it back and forth for fitment and or repair as it would be a nightmare to fix.
I personally could not recommend this product as a marine industry professional. I'm out!
Eden Island
Well-Known Member
Dumb question. Does this technology have a place in duoprop applications like my Volvo D3? The duoprops claim ~30% increase in efficiency over single prop. Would toroidal props increase that further? Do they exist?
Stainless duoprops were about $2500 five years ago. What would toroidal run?
Stainless duoprops were about $2500 five years ago. What would toroidal run?
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