Prop advice on a PT175 w/ 60 hp Merc 4 S

[okhawg]

So ran pretty much the same speed as it did with the 3 blade looks like. Do you like the 4 blade overall? Besides the holeshot how about in turns and while cruising? I would try it again without the whale tail just to see how it does. What trim level did it start to porpoise was it only when you tried to trim it out alot to gain top speed?

I do like the holeshot, did a fairly hard left turn and no blowout. You had one of the 60's before on this hull, you know you don't get a lot of trim out of it, and I was trimming to the max as much as I normally do. I'll try again Tuesday.

[TritonTRXV8]

I do like the holeshot, did a fairly hard left turn and no blowout. You had one of the 60's before on this hull, you know you don't get a lot of trim out of it, and I was trimming to the max as much as I normally do. I'll try again Tuesday.

I could get the motor trimmed maybe just above level and that was about it. Mid 30s seems to be the norm. Try it without the hydrofoil and let us know.

[okhawg]

Tried the 4 blade 14p Spitfire today with no wind and whaletail off. Exactly the same as with the whaletail, except it planed quicker before. 34 mph and 5700 rpms, it porpoises above 5700. Wondering about a Solas 3 blade 14p. It's like 3/4" larger in diameter, might be enough to lower the motor to 6000 or less.

[TritonTRXV8]

How hot is the weather where youre at? Not uncommon to see a couple hundred rpm drop in wot this time of year from the heat. Since your engine is rated for 6000 rpm you have some playing room here. I would try the 3 blade if you can to see how it does.

[okhawg]

How hot is the weather where youre at? Not uncommon to see a couple hundred rpm drop in wot this time of year from the heat. Since your engine is rated for 6000 rpm you have some playing room here. I would try the 3 blade if you can to see how it does.

Funny you should ask that, its July 29 in Oklahoma and it was about 63 degrees this am. Cool at 34 mph. As all know, this prop stuff isn't black and white.

[TritonTRXV8]

Are you still wanting to stay with an aluminum prop? Honestly with this prop you are within the rpm range but since it was so cool would be better to be at 5900-6000 rpm especially via smartcraft.

[gatorglenn]

I have the same hull as you, with the 2006 PT 175. It is 54 inches on the bottom of the beam of 83 inches. Unlike the newer models with a 60 inch bottom and 89 inch beam. My motor is mounted in the second hold down from the top. My cavitation plate is quarter of an inch above the most bottom of the boat. I tried the 14 pitch by 10.1 Spitfire prop and did not like it at all. I found that I had way too high rpm's and it would blow out very easily by trying to trim the motor out. I put my 14 pitch black max three blade back on and with the warmer water as Roy indicated , between 75 and 83° between two different lakes I could actually trim all the way out and run at 6000 RPMs with full tank of gas my 210 pounds and about 40 pounds of fishing gear. I've got a top speed of 37.8 GPS on choppy water, and 38.1 on slick water. I have a quick silver/Silverado stainless steel prop coming and I'll let you know how it runs. I like the way it runs now my only concern is, earlier this year in April when the water tenant was in the 40s I couldn't trim all the way out. It would cavitate but not over rev. So I'm going to stick with the three blade and put the four blade on eBay. I hope this might help. The only difference I see between my set up and most others, is that the newer models seem to mount the motor all the way down in the top hole.

[TritonTRXV8]

Those numbers with the 3 blade mirror mine when I had the 60. Mine was mounted all the way down as well.

[gatorglenn]

Hey Roy, if I'm right when i say new models yours is also 60 inches on the bottom and 89 in the beam. I'm just wondering if the difference in the model change in size is why they started mounting them all the way down , as compared to most of them in my model, second hold down. Or could it be difference between a 2006 four stroke or 2008 is the lenght of the motor any different.

[TritonTRXV8]

That very well could be. Mine is a 60" bottom 89" beam model. The engine specs are exactly the same tho both are 20" shaft engines. Actually the engine on mine was a 2007 model on a 2008 boat.

[gatorglenn]

Okay, with me and Okhawg having the same problem with RPMs being high. A 16 pitch prop if we could find one I feel would be the best with the smaller hull. I'm anxious to see how that three blade prop he's been talking about with the little bit higher diameter works.

[TritonTRXV8]

Having the engine 1" higher could increase the rpm by about 100 or so. Did you ever try a 15p 3 blade prop? 16p just seems a little big for this motor and it has a higher gear ratio to of 1.83:1.

[gatorglenn]

No I didn't try a 15 pitch but that's what I'm going to do I guess. I didn't mean 16 I meant 15 fat fingered that one. I saw a YouTube video of a lowe sportsman camo boat, it was the 16 footer with the 60 hp 4 stroke on it. They did a performance test, and they were running a 15p by 10.1 3 blade on it. I can't find 83 blade in that diameter. So I'm wondering if it was really a 15 pitch 10.14 blade Spitfire. But the size of their boat was not very much smaller than mine. Overall I think the length of my boat, is about 8 inches longer than that boat and almost the same identical size on the bottom. So that really got me wondering! Youget can take a look at the YouTube video it's on boat test.com but it's also on just regular Safari on the Internet Lowe's sportsman 16 performance test Google that. Let me know what you think.

[TritonTRXV8]

Mercury Prop Sale - Discount prices - Quicksilver Mercury Props

I found a 15P that would work but its a 10 1/8" diameter. I watched that video and a 15P may certainly work well. What are the specs for your model is it still 17' 7" in length?

[okhawg]

I've been debating and talking to a few folks about the prop. I thought about the larger diameter Solas 3 blade 14p. Now I thinking along the lines of the above conversations, and try the 15p. Motor turns a little over 6000 with the stock 14p, when its warm. The 15 should lower it to 5800 or so, and during the winter I might be right back at 6000. If I go with the 14p, then during the cold I'll be higher. Now the question is the Mercury 15p is 10.125" diam. and the Solas is 11", thinking the Mercury. I'll call the local dealer first of the week and see if they have a loaner.

[gatorglenn]

My 2006, has a length of 17'3", 54 inch bottom and 83 inch beam, with the transom height of 22 inches. As the numbers go it don't sound like a lot but as we will know in boat terms it is a huge difference. I've seen my boat up side of a newer model and it looks a lot smaller it almost makes it look like a 16 foot boat. But I really like the layout, and the ride, I don't get any of that porpoising problem that a lot of 10 boats have. My only problem is is trying to find the right prop to get these RPMs down where they should be. It is quite funny to see people's expression when they See a 60 hp come by them trimmed all the way out running really smooth with a rooster tail a foot and a half higher than the motor. Roy, where did you find that 10 1/8 inch 15 P prop at it sounds like the same one that was on that video.

[TritonTRXV8]

My 2006, has a length of 17'3", 54 inch bottom and 83 inch beam, with the transom height of 22 inches. As the numbers go it don't sound like a lot but as we will know in boat terms it is a huge difference. I've seen my boat up side of a newer model and it looks a lot smaller it almost makes it look like a 16 foot boat. But I really like the layout, and the ride, I don't get any of that porpoising problem that a lot of 10 boats have. My only problem is is trying to find the right prop to get these RPMs down where they should be. It is quite funny to see people's expression when they See a 60 hp come by them trimmed all the way out running really smooth with a rooster tail a foot and a half higher than the motor. Roy, where did you find that 10 1/8 inch 15 P prop at it sounds like the same one that was on that video.

Mercury Prop Sale - Discount prices - Quicksilver Mercury Props. This is where I found it. Pretty good pricing as well.

[TritonTRXV8]

I've been debating and talking to a few folks about the prop. I thought about the larger diameter Solas 3 blade 14p. Now I thinking along the lines of the above conversations, and try the 15p. Motor turns a little over 6000 with the stock 14p, when its warm. The 15 should lower it to 5800 or so, and during the winter I might be right back at 6000. If I go with the 14p, then during the cold I'll be higher. Now the question is the Mercury 15p is 10.125" diam. and the Solas is 11", thinking the Mercury. I'll call the local dealer first of the week and see if they have a loaner.

For the size and gearing of the 60hp class (1.83:1 gears). My personal choice would be the 10 1/8".

[gatorglenn]

Ok, tell me will the 10.1 even though it is a 15 pitch, it's going to spin up faster. Will it want to blow out as easy as the spitfire, on trimming out.

[TritonTRXV8]

I think the 10.1 will be fine. That boat in the video we watched had great numbers with that prop.