4 Blade Propco Slingshot Prop For My DF225?

[Sunstate78]

I have an '07 Suzuki DF225 on my boat and get only 5200 at WOT. The current prop is a Suzuki 3X16X20. I want to move to an 18.5 pitch to increase my RPMs as Suzuki recommends I get closer to 5500-6000 rpm.

While looking for the 18.5 pitch prop, I came across a company called Propco owned by Peter Dean out of Georgia who has a long sucessful career in racing and building props. After giving him my boat specs and issue, he recommends a 4 blade prop vs. 3 blade (15.5 diameter) and an 18 pitch called a Propco Slingshot. He guarantees a huge pickup in RPMs and top end speed, better handling in rough water, and up to a 40% increase in fuel economy (extremely hard to believe).

Has anybody heard of the Propco Slingshot and is it compatible with the Suzuki? He's charging $710 for the prop. I know he manufactures them.
Thanks

[Moonlighter]

No, never heard of them.

You must have a heavy or big boat for that engine to be only be getting 5200rpm! At those revs the engine is definitely lugging badly and if you keep running it like that you will kill it! But I suspect you already know that.

That engine needs to be propped to get close to, if not right on, 6000rpm.

Also check your engine height. An engine buried too deep will cause drag and reduce rpm's. Quite an important thing to get right and far better to do if before playing too much with props. Anti-vent plate should be skimming the surface, not under water, at a fast cruise speed with engine trimmed normally.

Given you are in the U.S., you could talk to Ken from the Propgods, they have an excellent reputation for propellor knowledge and advice.

[BillCon]

I, have an 18 hydrasports and run 4x13.5x22 on a dt150 I, can tell you on mine, the 4 blade prop will not slip even on the tightest turns, roughest water and hard launches, I'm not sure about what some say that you loose 1-3 mph on top ends compared to a 3 blade I, dont have one to test, but I, will never go back to a 3 blade, and I, agree with moonlighter do make sure your motor isnt to deep.

[Sunstate78]

[/B]r;17138]No, never heard of them.

You must have a heavy or big boat for that engine to be only be getting 5200rpm! At those revs the engine is definitely lugging badly and if you keep running it like that you will kill it! But I suspect you already know that.

That engine needs to be propped to get close to, if not right on, 6000rpm.

Also check your engine height. An engine buried too deep will cause drag and reduce rpm's. Quite an important thing to get right and far better to do if before playing too much with props. Anti-vent plate should be skimming the surface, not under water, at a fast cruise speed with engine trimmed normally.

Given you are in the U.S., you could talk to Ken from the Propgods, they have an excellent reputation for propellor knowledge and advice.

Thx. I emailed Ken and am awaiting his opinion. I need to get my motor professionally assessed as to height as I have no idea what to look for (don't know what a anti vent plate is). Is this something they can assess out of the water or does it need to be in the water? Thx for your help.

[Grumpy56]

Sunstate, checking the engine level is something you can do yourself. On your engine just above your prop is a flat plate. (Not that I would do it, but if you were in the water trying to get out, it is the plate that you would put your foot on the to climb back into the boat.) Hopefully this is enough info to understand what the anti-ventilation plate is.

When your boat is running on-plane this plate should be right at water level. Often it is to far down, causing more drag on the motor/prop. What I would suggest is have a driver run the boat on plane, close to max RPM and CAREFULLY lean over the transom and take a few pictures of the plate. Is it right a water level, or is it underwater? If it is too low, underwater, a dealer can raise your motor height pretty easy. I expect about 30 - 45 minutes of labor to raise the engine. Again be really careful taking the pictures while someone is driving your boat.

I would NOT raise an engine myself, but here is what basically needs to be done FYI. If you stand behind your boat you will see a total of 4 bolts that hold your engine to the boat. Two low bolts and two high bolts. I believe the lower ones are in a slot, so the engine can move up or down. The upper bolt is thru a hole, there are four or five different holes on each side in a vertical line. To raise the engine, it needs to be supported, the lower 2 bolts need to be released, and the two upper bolts are removed from the hole. The engine is raised and the bolts are reinstalled in the proper hole. Not hard IF you have a way to support the weight of the engine and raising it to install the bolts in the next higher boat hole. Just remember you are dealing with about 500 pounds and $15,000 worth of engine. So if you do NOT have the proper equipment, best leave the engine height adjustment to a professional.

Back to the pictures, if you take them, post them here or send them to Ken at Prop Gods. Another good guy to work with on prop issues is Marus at PowerTech props. They only sell their props and a lot of people use them.

Best of luck,
Craig AKA GRUMPY

[Sunstate78]

Sunstate, checking the engine level is something you can do yourself. On your engine just above your prop is a flat plate. (Not that I would do it, but if you were in the water trying to get out, it is the plate that you would put your foot on the to climb back into the boat.) Hopefully this is enough info to understand what the anti-ventilation plate is.

When your boat is running on-plane this plate should be right at water level. Often it is to far down, causing more drag on the motor/prop. What I would suggest is have a driver run the boat on plane, close to max RPM and CAREFULLY lean over the transom and take a few pictures of the plate. Is it right a water level, or is it underwater? If it is too low, underwater, a dealer can raise your motor height pretty easy. I expect about 30 - 45 minutes of labor to raise the engine. Again be really careful taking the pictures while someone is driving your boat.

I would NOT raise an engine myself, but here is what basically needs to be done FYI. If you stand behind your boat you will see a total of 4 bolts that hold your engine to the boat. Two low bolts and two high bolts. I believe the lower ones are in a slot, so the engine can move up or down. The upper bolt is thru a hole, there are four or five different holes on each side in a vertical line. To raise the engine, it needs to be supported, the lower 2 bolts need to be released, and the two upper bolts are removed from the hole. The engine is raised and the bolts are reinstalled in the proper hole. Not hard IF you have a way to support the weight of the engine and raising it to install the bolts in the next higher boat hole. Just remember you are dealing with about 500 pounds and $15,000 worth of engine. So if you do NOT have the proper equipment, best leave the engine height adjustment to a professional.

Back to the pictures, if you take them, post them here or send them to Ken at Prop Gods. Another good guy to work with on prop issues is Marus at PowerTech props. They only sell their props and a lot of people use them.

Best of luck,
Craig AKA GRUMPY

Awesome! Thank you so much. I've been watching YouTube videos tonight and have a pretty good idea as to what I should be looking for. I will also measure the plate vs where it is in relation to the keel to see if it initially measures too low. Will post pics when I take it out this weekend. Thanks again for your help.

[Moonlighter]

Craig's explanation of what to do is spot on the money. It's easy to do, just be careful. A trick we found is to put a red sticky dot each side on the top of the anti-vent plate so it makes I easier to see in the water that is splashing around.

As you will have seen, it is pretty well accepted that you need to get the engine height right, and then start playing with props.

I would add is that 4 blade props usually (not always) give greater stern lift than a 3 blade prop. So if you are setting engine height using your existing 3 blade Suzuki prop, I would suggest you get the height to where the anti-vent plate is JUST skimming the surface of the water. That way, when you try the 4-blade, the extra lift hopefully brings it into perfect position.

The other thing is that I don't think you would gain much by going to that very expensive custom made prop that you mentioned first up. There are plenty of very good, high quality off the shelf stainless props available that will do a fine job for you at less cost than that prop.

Plus, dealing with someone like Ken, if the first prop you try from him isn't right, he will exchange it for another and another until you are satisfied. Will the other guy do that?

[Sunstate78]

Craig's explanation of what to do is spot on the money. It's easy to do, just be careful. A trick we found is to put a red sticky dot each side on the top of the anti-vent plate so it makes I easier to see in the water that is splashing around.

As you will have seen, it is pretty well accepted that you need to get the engine height right, and then start playing with props.

I would add is that 4 blade props usually (not always) give greater stern lift than a 3 blade prop. So if you are setting engine height using your existing 3 blade Suzuki prop, I would suggest you get the height to where the anti-vent plate is JUST skimming the surface of the water. That way, when you try the 4-blade, the extra lift hopefully brings it into perfect position.

The other thing is that I don't think you would gain much by going to that very expensive custom made prop that you mentioned first up. There are plenty of very good, high
quality off the shelf stainless props available that will do a fine job for you at less cost than that prop.

Plus, dealing with someone like Ken, if the first prop you try from him isn't right, he will exchange it for another and another until you are satisfied. Will the other guy do that?

Excellent. Thank you. When running on plane close to WOT, should I trim at all or leave the engine all the way down when observing plate depth?

[Sunstate78]

Sunstate, checking the engine level is something you can do yourself. On your engine just above your prop is a flat plate. (Not that I would do it, but if you were in the water trying to get out, it is the plate that you would put your foot on the to climb back into the boat.) Hopefully this is enough info to understand what the anti-ventilation plate is.

When your boat is running on-plane this plate should be right at water level. Often it is to far down, causing more drag on the motor/prop. What I would suggest is have a driver run the boat on plane, close to max RPM and CAREFULLY lean over the transom and take a few pictures of the plate. Is it right a water level, or is it underwater? If it is too low, underwater, a dealer can raise your motor height pretty easy. I expect about 30 - 45 minutes of labor to raise the engine. Again be really careful taking the pictures while someone is driving your boat.

I would NOT raise an engine myself, but here is what basically needs to be done FYI. If you stand behind your boat you will see a total of 4 bolts that hold your engine to the boat. Two low bolts and two high bolts. I believe the lower ones are in a slot, so the engine can move up or down. The upper bolt is thru a hole, there are four or five different holes on each side in a vertical line. To raise the engine, it needs to be supported, the lower 2 bolts need to be released, and the two upper bolts are removed from the hole. The engine is raised and the bolts are reinstalled in the proper hole. Not hard IF you have a way to support the weight of the engine and raising it to install the bolts in the next higher boat hole. Just remember you are dealing with about 500 pounds and $15,000 worth of engine. So if you do NOT have the proper equipment, best leave the engine height adjustment to a professional.

Back to the pictures, if you take them, post them here or send them to Ken at Prop Gods. Another good guy to work with on prop issues is Marus at PowerTech props. They only sell their props and a lot of people use them.

Best of luck,
Craig AKA GRUMPY

BTW, I just measured the lcoation of the plate vs. the keel and the plate is approximately 1.5-2 inches above the lowest point of the keel so it's not sitting low from that perspective. Out of the 5 possible bolted positions, the engine is bolted in the middle holes (3rd from the top or bottom) so nothing noteworthy here. The true test will be in the water! Thx

[Grumpy56]

Excellent. Thank you. When running on plane close to WOT, should I trim at all or leave the engine all the way down when observing plate depth?

I would trim the engine like you normally run it. Again, be carefully taking the pictures or looking over the transom with someone else driving the boat. When I did it I reached out with the camera and took a bunch of pictures and hoped for a few good ones.

[Sunstate78]

I would trim the engine like you normally run it. Again, be carefully taking the pictures or looking over the transom with someone else driving the boat. When I did it I reached out with the camera and took a bunch of pictures and hoped for a few good ones.

I'm thinking of rigging my go pro back there so I can get a consistent video without anything stupid happening. Thx

[Solarman]

The rule of thumb is... 2 blades are for speed, but slower out of the hole, two blades don't grab much water for take off. But at about 15-20 mph they start to grab and go.
Three blades are the most common, for combined power and speed, and getting up on plane. Grab good at take off, and good on top end speeds.
Four blades are for heavier boats, loaded boats, more power at take off, to get a heavier boat up on plane, sacrificing a few miles per hour top end, for more power to get going.

The pitch and travel of a prop, are the important info to change RPMs.

If you don't have an extremely heavy boat, ask Ken what will get you to 6k RPMs. It sounds like you're high enough above keel?

[Sunstate78]

The rule of thumb is... 2 blades are for speed, but slower out of the hole, two blades don't grab much water for take off. But at about 15-20 mph they start to grab and go.
Three blades are the most common, for combined power and speed, and getting up on plane. Grab good at take off, and good on top end speeds.
Four blades are for heavier boats, loaded boats, more power at take off, to get a heavier boat up on plane, sacrificing a few miles per hour top end, for more power to get going.

The pitch and travel of a prop, are the important info to change RPMs.

If you don't have an extremely heavy boat, ask Ken what will get you to 6k RPMs. It sounds like you're high enough above keel?

The boat itself is 3540 lbs, add 600lbs for the motor, 400lbs of gas, supplies, 2-3 guys & you're up close to 6000lbs. I'd say it's a heavy load to haul. Funny thing is I've never seen a 4 blade prop On this boat (2007 Pro-Line 23 Sport).

[Moonlighter]

I'm thinking of rigging my go pro back there so I can get a consistent video without anything stupid happening. Thx

A go-pro on a pole is a great idea. Get some video from both sides of the engine.

And as Crag said, when you get up to a good medium to fast cruise speed, trim the motor out to the normal comfortable position where the engine is running at its best.

Obviously, it will be best to pick a nice smooth patch of water to do the test.

Good luck, look forward to seeing the results. If you upload the video to photobucket or u-tube then copy the link into a post here, will be able to see it.

[Sunstate78]

So here's the deal. I gave the motor 4 runs and took video on all runs. The first couple of runs clearly indicated that the motor was sitting too low even after trimming a little.

What I did on the 3rd run was instead of watching my trim gauge, I kept trimming up as I watched my speed on a phone app. At WOT, When the speed leveled off, I hit 45 mph and 5800rpm. Bingo. When I looked at my trim gauge, the needle was above the half way mark almost to 3/4. I was shocked as all my gauges are new and wouldn't think of trimming that high. When I went to the back of the boat the plate was properly just above the water. I feel stupid. Should have done this all along, I'm wondering if the trim guage needs to be calibrated somehow.