Toroidal propellers: gas burn reduction potential?
- Thread starter pescador
- Start date
ship happens
Well-Known Member
pescador
Well-Known Member
Not up on my Emojis. Hope that's good.
ship happens
Well-Known Member
Put it this way, I hope for all of what you said as well. Friends?
ship happens
Well-Known Member
Right. I wanna see this in actual action. Been a fuss for a while. I want to put it against some props that I know are right in there with all the things that those boys are claiming it to be. I'll put that one on record.
Gotta fire up that smoker after all its superbowl
Sharphooks
Well-Known Member
I know one of the guys who was on board this boat and involved in a two-day Sharrow test. It’s a 30 footer with a 9 foot beam and twin 300’s so I’m highly motivated to get the straight scoop from him.
The reduction in decibels is low on my list of the attributes I’d consider spending money for but extended range is something that has my full attention
According to the test results, the big gain in range is from troll speed up to the middle of the RPM curve. I can imagine the FLorida guys will yawn at these results because they all seem to be WOT kind of guys
From the test results:
QUOTE
Most boat owners are fanatical about two things, one matters, and one doesn’t: top speed and fuel consumption at cruising speeds. The fuel consumption of a boat such as the Duckworth 30 Offshore XL is particularly critical because of the distances involved getting to the fishing grounds.
The Duckworth propped with Sharrows has greater range at any speed under 32 mph, and a best cruise planing speed that is 38% farther at nearly 25 mph, and 24% more range at 30 mph. At trolling speeds, as can be seen in the chart below, the boat has 34% greater range.
UNQUOTE
The reduction in decibels is low on my list of the attributes I’d consider spending money for but extended range is something that has my full attention
According to the test results, the big gain in range is from troll speed up to the middle of the RPM curve. I can imagine the FLorida guys will yawn at these results because they all seem to be WOT kind of guys
From the test results:
QUOTE
Most boat owners are fanatical about two things, one matters, and one doesn’t: top speed and fuel consumption at cruising speeds. The fuel consumption of a boat such as the Duckworth 30 Offshore XL is particularly critical because of the distances involved getting to the fishing grounds.
The Duckworth propped with Sharrows has greater range at any speed under 32 mph, and a best cruise planing speed that is 38% farther at nearly 25 mph, and 24% more range at 30 mph. At trolling speeds, as can be seen in the chart below, the boat has 34% greater range.
UNQUOTE
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ship happens
Well-Known Member
Come on boys let's test those props on a boat that is worthy of the west coast. No ducks. No geese. Hunting season ended. 1
All I hear is yep, percentage at cruise yadi ya, let's here rpm and running conditions and put that on a glass boat
All I hear is yep, percentage at cruise yadi ya, let's here rpm and running conditions and put that on a glass boat
noluck
Well-Known Member
that is exactly where prop slip is the most, low to mid cruise speed, prop slip decreases as the hull friction decreases, i have run a boat at 4% prop slip but was at 70mph to do it, 27pitch ballistic prop was needed, it had enough cup in the prop, the minuet you hold the water on the blade efficiency will increase, that is what that prop is doing with the loop
BC Coast Pilot
Well-Known Member
Graphs are compared to a "traditional" prop. Those gains are very similar to gains claimed by props already on the market........I'm not in.....yetCome on boys let's test those props on a boat that is worthy of the west coast. No ducks. No geese. Hunting season ended. 1
All I hear is yep, percentage at cruise yadi ya, let's here rpm and running conditions and put that on a glass boat
This test is a bunch of bs.They are fudging the numbers on a conventional prop. I own a similar dimension aluminum with a comparable power package and the conventional numbers are way off at 3000-4000 (where the engines should actually be run).
This graph shows a the conventional 15.5 by 17 doing 16mph at 4000 rpm. This must be with the worst props you could possibly find. Maybe some weird old 2 blade a dogs been chewing for years. I want this to be legit but this is total crap.
I agree with some of the other posts. If these are legit why the bs marketing. The above graph is a complete joke. Shame! Shame!
Rain City
Crew Member
That's a great point
Sharphooks
Well-Known Member
Maybe, but seven guys and more then likely a full tank of gas? They were tracking the power curve and with all that weight a “traditional” prop (Saltwater Series?) probably struggled a bit to get out of the hole....I doubt they would have been stuck at 16 Mph for long at 4K if they had throttled down and kept the twins in the 4 K RPM band
pescador
Well-Known Member
Dunno if this props the GOAT, but what i know is that current props aren't very efficient. They've been around since Archimides. Time for someone to come up with a new design. Not sure about you but putting $600 worth of fuel in boat boat every week in the summers becoming very unappealing Lets get Elon on this one now
ship happens
Well-Known Member
Hey like I said, I'll call them on Monday and if they are willing to allow my marine outfit to run a test prop at at least some kind of dealer demo price, I would toss some coin to see what happens. I'm leaning to 80 percent ********
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wildmanyeah
Crew Member
The advantage is it’s suppose to reduce propeller tip turbulence.
Like how a lot of air plane wing tips now have winglets, to reduce the turbulence in the tip of the wing. Airlines seen significant savings. See winglets on most of westjet planes now.
For drone propellers it’s reduced noise and increased preformace
I seen tests with cpu Fans and it Doesn’t seem to have done Mach as cpu Fans already have a case around the fan blades.
If that translate to boats I think that’s yet to be seen. This one company seems to think so.
Like how a lot of air plane wing tips now have winglets, to reduce the turbulence in the tip of the wing. Airlines seen significant savings. See winglets on most of westjet planes now.
For drone propellers it’s reduced noise and increased preformace
I seen tests with cpu Fans and it Doesn’t seem to have done Mach as cpu Fans already have a case around the fan blades.
If that translate to boats I think that’s yet to be seen. This one company seems to think so.
zloy
Member
Something is off (BS) with the first graph. I get at least 20 knots (~23 mph) 4000 rpms with twin Yamahas 300 on my heavy-butt 33' Grady. If I recall correctly 4500 rpms gets me to like 28-29 knots. How come their Duckworth (lighter, shorter) can't beat it with the same engines with "standard" props?
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