Sharrow Marine - Showdown in Paradise by BoatTEST.com

[Music] hi i'm steve from boattest.com and today we're in beautiful saint john in the u.s virgin islands to do a third party test of a catamaran propped with a set of conventional propellers and a set of cheryl loop propellers we at protest think that 2022 will go down in the boating history books as a year that several new technologies got serious traction and started changing the way we go boating first diesel outboard engines are now being accepted in military commercial and recreational applications we think you'll be seeing a lot more of them in the future second numerous high horsepower electric motors well over 100 horsepower both inboard and outboard are being launched this year both in north america and in europe they have extremely high torque like the diesel outboards and also need a way to harness that prodigious torque effectively for efficient propulsion and third the cheryl prop after years of testing by bow test outboard engine makers and numerous boat builders is increasingly being adopted to propel boats where an increase of 30 or more of mid-range efficiency is desired in this video we'll show you the very first independent third-party test of the cheryl props on a 300 horsepower diesel outboard this test will settle the question as to whether or not this new technology can outperform conventional prop designs in high torque applications such as diesel electric motor and high horsepower gas outboard engines let's get the voodoo underway and see how she performs this test is nothing short of a showdown between conventional technology represented by a five blade prop made by one of the country's most respected companies and the new technology of a cherokee propeller on a high torque diesel engine first thing we need to do is get something out of the way this was not a normal test where we're testing an off-the-shelf propeller against an off-the-shelf cheryl propeller both of them were customized there are simply no propellers that were made for this boat the normal propellers were custom designed then the cheryl propellers were custom designed as well they took their entire engineering team looked at all the cad drawings of this all the specs the weights came up with a propeller for this boat sight unseen pretty amazing process the vessel we're testing the props on measures 57 feet length overall with a beam of 26 feet and a draft of three feet she weighs approximately forty thousand pounds the twin three hundred horsepower diesels are made by oxy and have a three liter inline six bmw diesel engine with the belt driven prop through a 1.59 to 1 gear ratio the engine is rated at 680 newton meters of torque at 1750 rpm according to the company how much power is 680 newton meters of torque well to give you an idea each one of the two electric motors in a tesla model s has 650 newton meters of torque oh the trim time's right there chris shoop designed voodoo he had the foresight to realize that if he had inboard diesels and they had to be replaced or a major overhaul was needed they would literally have to be cut out of the boat a process that would keep his vessel out of business for at least three months he had five requirements for the new props propel the boat at 18 knots at 3200 rpm deliver at least 21 knots at wide open throttle be much more economical than his current props make maneuvering at the dock easier and be quiet with smooth running and no vibration the first thing we did was to put on the new custom-made five-bladed props and captain chris made sure they were securely on it's not unusual for large heavy boats powered by inboard diesels to have five or six plated props and this had five blades their geometry was 17 inch in diameter with a 12 inch pitch as always we conducted our performance trials in reciprocal directions the test was conducted on an 85 degree day with 69 relative humidity and 10 to 50 mile per hour winds in a protected area with less than one foot of wind blown chop while we took all of our normal readings in this video we'll show only a few with conventional props at 2 800 rpm voodoo went 14.4 miles per hour burning 13.3 gallons per hour for 1.1 miles per gallon which is not bad for a 57 foot 40 000 pound boat with 12 passengers aboard now we're going to see if the five-bladed props will achieve chris hoop's desired speed at 3200 3200 rpm at 3 200 rpm we recorded 16.8 miles per hour when we convert 16.8 miles per hour to knots we find that the boat was going only 14.6 knots and thus fell short of catherine shoop's first requirement by 3.4 knots now let's see how fast she goes at top speed 4000 rpm when we ran the boat up to a wide open throttle setting of 4000 rpm our speed topped out at 20.8 miles per hour or 18.1 knots missing shoots target speed by 2.9 knots by this time we had run the boat long enough to know that there was significant vibration with the five blade of props vibration by its very nature causes more noise although we were not able to measure it and it also adds to fatigue when it came time to running voodoo in reverse watch what happens as i try to come up on a mooring buoy with the five-bladed props with the engines in reverse the boat just keeps on moving forward the ball goes right under the boat it took a strong blast to reverse to get the job done virtually all conventional props are designed to go forward not aft anyone who has put an outboard motor in reverse knows that so now the question was could the sheryl prop hit the owner's speed requirements to find out we needed to change props to save time the crew tied voodoo up to a mooring and did a prop change putting on the cheryl props shower engineers designed a 14.5 diameter by 11 inch pitch three loop stainless steel prop once installed off we went right away with the sharrow props i saw a difference in handling when i took the helm i had more control when backing off the mooring and there was no longer any vibration during maneuvers already the show props met two of chris shoop's five requirements the vibration was gone even in reverse where nearly any boat will rumble with almost any prop and she stopped and backed down with remarkable positive control unlike with the five blade of props but would the shadow props be able to meet chris's speed criteria let's find out 26 26. [Music] it's chris's job to throttle the entrance to the rpm i call out and then i wait for the boat to settle in at that speed and then record the data on my ipad [Music] now let's bring it up to 2800 please 28. [Music] 2 800. i got 15.9 gallons chris confirms that he has the rpm steady i then check the ship's instruments along with my own gps and sound meter okay let's do 3000 rpm please and now the moment of truth this is the showdown in paradise okay 3200 coming up to 32. at 3 200 rpm on this run you can see that we're burning 20.1 gallons per hour and going 19.5 knots now remember we perform reciprocal runs both into and with the current and wind than average the numbers so the numbers you see here will not be the final numbers but after completing the reciprocal run at 3 200 rpm the average speed was 19 knots which is 21.9 miles per hour with an average fuel burn of 21.1 gallons per hour the cherry prop speed shoop speed requirement at 3200 rpm by a full knot now let's compare fuel economy between the old technology and the new at 18 knots where captain chris wants to run his boat most of the time here the conventional props get 0.72 miles per gallon and the cheryl props get 1.05 miles per gallon which is a remarkable 46 improvement now we go for the big prize top speed will the boco 21 knots as required by the owner okay 3800 got 30.5 gallons an hour 23.2 knots and 26.5 miles an hour okay we're all set we can come about running a reciprocal course we saw right away that we were bucking a slight current and our speed over the ground at wide open throttle dropped to 20.85 knots or 24 miles per hour but when we averaged the two we got an impressive 21.7 knots or 0.7 more than the hurdle required now we could check the fifth box when we compare speeds at all rpm shadow props are faster and above 2400 rpm dramatically so at wide open throttle they were 27 faster at all speeds except one the sheryl props were more fuel efficient than the five-bladed props look at this chart and you can see that at idle speeds the sharrows were 27 more fuel efficient and at the other end of the spectrum where the 5 blade prop tops out at 18.1 knots the new technology was 46 percent more fuel efficient why is the sheryl prop design so much more fuel efficient than old technology well simply stated the shuttle props grab the water much better than any conventional prop by doing that it is also able to transfer the forward thrust more effectively to the water we shot the wake of the five blade of props at 4000 rpm in slow motion so you could clearly see what is going on look between the wake for first the starboard and then the port prop wash notice the thick trail of turbulence because these diesel outboards do not rip the exhaust out through the hub as virtually every gasoline outboard motor does we can't for the first time ever actually see the tremendous amount of cavitation that is going on not only is this why the conventional props are noisier but also why their advance rate through the water is so low just take a look at these numbers and see what i mean the red line is the actual number of inches that the 5-bladed prop with a 12-inch pitch actually moved forward not 12 inches but at the left-hand starting point at 650 rpm just 7.76 inches and at 4 000 rpm the old technology was doing slightly worse advancing only 7.54 inches the blue line is the shutter prop with an 11 inch pitch and as can be seen it advanced farther than the conventional prop in each data point except one note that at 3200 rpm the shuttle prop advance of 10.05 of its possible 11 inches or was 91 percent efficient the best the five blade could master was at 1 000 rpm where it advanced 8.22 inches of possible 12 to be 69 efficient now let's look at a video clip of voodoo being propelled by the cheryl props at 2600 rpm going 13.7 knots one of the lower advance rates as you can see there's only a thin string of bubbles trailing the boat indicating very little cavitation while we were in the virgin islands the price of diesel fuel was nine dollars per gallon that means that fuel is capped at chris's single biggest cost of doing business he does most of his running at 18 knots and with the sheryl props at that speed he'll save 40.50 per hour that certainly puts the high cost of this new technology in perspective well there you have it our showdown in paradise between new and old prop technology on a pair of high torque diesel outboards as regular followers of boat tests know we have tested the sheryl props on small boats monohulls small cats and now this big heavy cat and the answer is always the same in the mid rpm range where most people spend most of their time running the cheryl props are always around 30 percent more fuel efficient and also make the boat go faster there's more control and less vibration when backing down and that's my full test of the cheryl loop propeller for boattest.com i'm captain steve we'll see you on the water [Music] you

Channel: BoatTEST.com

Views: 96,396

Keywords: sharrow marine, best propellers, boattest, boattest.com, catamaran, oxe diesel outboard, oxe engines

Id: PYGChIUdTX4

Length: 12min 59sec (779 seconds)

Published: Wed Jun 15 2022