Couple of weeks ago I bought a “new to me” 218 Sailfish Walkaround with a F150 yamaha. My initial thought was the boat would be underpowered, but internet research says otherwise. I ran the boat and decided to make the purchase, but I would really like to get more performance from the rig, so I’m on a quest to find a more efficient prop.
Hull weighs 3000 lbs.
Length is 21’-3"
Beam is 8’-6"
Lenco trim tabs.
Here is what I’ve done so far…(all speeds are in statute MPH)
Original prop is a 14.5 x 15p 4-blade SS. The motor turns the prop at WOT 6000 rpms with a speed of 35MPH
I tried a 15 x 17p alum. WOT was 5200 RPM and around 30MPH.
I tried a 14.25 x 17p SS Reliance Series prop and WOT was 5400 RPM and 36.5 MPH.
I have a 13.75 x 17p SS ordered and am going to try it next.
I’m testing the boat with two batteries, 1/2 tank(50gal.) of fuel, 2 people on board, fresh water, little to no wind.
Sailfish web site says this boat/motor combo will hit 40mph with the way I’m testing it, but they don’t tell what prop. Yamaha doesn’t have a performance bulletin for this hull, but I’ve looked at similar hulls that they have bulletins on. Best match is the Seafox 216WA and they are turning a 13.75 x 17p and hitting 42MPH.
Does anyone here have any further insight, Sailfish owners group has been no help at all. Do you guys know anyone who has this set-up and is getting better performance data than what I have or at least coming close to the data put out by Sailfish? I don’t believe that a 15p 4 blade prop is the best fit.
I haven’t called Sailfish yet, but sent an e-mail that has yet to be responded to.
OBTW…I took it to my local yamaha mechanics and they checked the set-up on the motor and it’s installed correctly.
4 blade on a 4-stroke doesn’t have the advantages as on a 2 stroke. I think you will find the 13.75 x 17p SS will be a great prop. If you can’t get 5500-6000 RPM, you can try the same size prop with less cupping or go to a 13.5 x 17 stainless. Stainless have a lot more bite at full RPM due to cupping design and rigidity. Like the performance bulletins show, you’ll probably go fastest around 5900 RPM.
Make sure you test with the trim tabs up. Trim the motor up to get nose raised, which should get you max speed (you can experiment with this). Remember that GPS gets you speed over the earth, not speed through the water. You need to test at slack tide or in a lake to get a true measurement. In a river that has current, to get true speed, add speed in both directions and divide by two.
Good advice from 3Oaks. Props are mostly trial and error. On my boat I went through 5 before I found the best one. It’s good to have a dealer who will work with you and let you try them and swap them.
It sounds like you are real close to getting it right. If you haven’t, you might try raising your engine one hole position. The higher you can run it without ventilating, the more efficient it will be. It can be amazing how much difference an inch can make.
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
I’ve had props vary from box to box. If you go to Skipp’s Prop shop off cross county road and tell John exactly what you are looking for chances are he will get you right on the money. He can even work an existing prop and give you remarkable results. He’s let me take a couple with me for sea trial. Just as long as prop comes back in the same shape. He used to have a good many used props for sale, but I haven’t been to him in 4 or so years.
On the 4 blade, the only reason I’ve ever used one was to keep steering torque down on a straight cable Glitter boat. John worked that prop and put me from 76mph to 81mph. As I said he can do wonders with props.
On what Cracker said… One inch can make a world of difference . If you start changing your motor height, make sure when you sea trial it you turn it as hard as you can at as safe a speed you feel comfortable to make sure it doesn’t “blow out” at the new raised height.
What is your goal? Sounds like you are set on trying to run a 17P prop.
The problem that you are going to run into is that you are having to reduce diameter to get the rpm up. That is fine if you are running fast all the time in smooth water, but you will be reducing the ability to push the boat at slower speeds or when it is rough because the smaller diameter prop doesn’t have the blade area an will cavitate. You are also testing at what I consider light in good sea conditions.
Are you comparing your 218 Walkaround to other Sailfish walkarounds or the center console version. I would guess that the Sailfish is significantly harder to push than a similar size Sea Fox.
From what I am seeing the 15P is was the best choice.
Iain Pelto
Sea Hunt Triton 160 w/ 90 ETEC “JB3”
Native Manta Ray 14
Ditto on what Fred posted… Skips Prop Shop won’t steer you wrong and John knows his stuff!!!
Key West 19’6" CC 115hp Merc
14’ Fast Craft w/ 60hp Merc
Not sure why you are trying to mess with it. That 15P 4 blade looks good to go.
What are your goals? Higher speed? That new 17P may end up just right, but if you are happy with the RPM’s and speed of the future prop, I would really do a full test in rough conditions and a full load with both that prop and the 4 blade before cementing your decision. I bet the 4 blade will handle the rough stuff a lot better.
“Banana Pants”
Indigo Bay 170
90 Johnson
Wilderness Ride 115
Not looking so much for speed, (if speed was a real issue I would have gotten a 225 instead of the 150) mainly trying to get “optimum performance” or balance of best speed vs fuel economy.
The Sailfish website says this rig will run 40MPH at WOT, I’m no where close to that. The test data was gathered in similar conditions, light seas, 1/2 tank of fuel, 2 people, 1 battery, safety gear and a few pieces of fishing tackle. I’m trying “apples to apples”
Fuel economy means more to me than anything, but it seems like the 4 blade 15p is very easy to turn and not getting anywhere so the fuel economy will be down since it will take more turns of the motor to go the same distance.
If the smaller diameter 17p doesn’t work I will call the guy Fred mentioned and see what he says. May have to go back to a 15p with a larger diameter and have a little extra cup put into the prop.
Thanks for you guys input!
Another thing, there is an old Lowrance skimmer transducer mounted real close to the center line of the motor, just off to the starboard side of center. (maybe within 8" of center)
I have removed this and mounted my transducers over closer to the trim tabs. I think this transducer was allowing “early ventilation” of the prop. That would prevent me from getting good bow lift and hurt the performance also.