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| I have a Tuffy 1700 with a 115 hp Optimax. It currently has a 14 x 17 pitch 3-blade, Mercury BlackMax aluminum prop. The motor is mounted one hole up, and max RPM's are within acceptable range.
Since I've heard it has been used on several similarly set-up 1700's, I'm considering a 13 3/4 x 17 pitch, 4 blade Mercury Trophy Plus SS prop.
My question is, what changes in performance should I expect? I'd be particularly interested in how max RPM's, minimum on-plane speed, hole-shot, and especially prop torque/boat-lean are likely to change. Other comments or overall performance/handling comments would also be very welcome.
If possible, I'd love to hear from VMS (who seems to be the resident expert on props), ttrap (who I think may have a 1700 with 115 opti and 17p trophy plus), other 1700 owners with comments on their set-up, and sworrall or anyone from Tuffy with explicit knowledge of the boat.
Thanks!
Edited by PJV 3/14/2014 11:48 AM
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Posts: 3508
Location: Elk River, Minnesota | Hiya,
First off, thank you for the compliment. 
In changing from aluminum to steel, you will generally see about a 200 or so RPM drop because a steel prop will flex quite a bit less than an aluminum in the same pitch and diameter. Now...in your case, you have a few more things changing, because you are dropping diameter by 1/4", which is usually an increase of 100 or so RPM. So...with just that in a 3 blade model, you would be down roughly 100 RPMs. It the trophy prop has some good cupping on the trailing edge as compared to the black max, so it could potentially reach a 200 or so drop in RPM.
Now...the trophy is also a 4 blade prop, so there will be another 200 or so RPM drop due to adding the blade. The reason this happens is due to the extra friction you are gaining due to more surface area of the prop in contact with the water. Given the height of your motor now, I would suspect you would see a drop of about 400 or so RPM from where you are currently.
BUT!!! If your motor can move up, you will gain some of that back without any loss of handling due to the 4th blade...with the potential of going to the highest bolt hole position and still have a prop grabbing quite well. It is possible you could gain back about 200 rpm.
Performance of the boat will be with handling more than anything. Hole shot might increase a little, but since you are turning the same pitch, I don't believe it will change to any significant amount.
With the 4 blade steel prop, you will have more control over trimming which in this case you will feel your entire boat might be lifted more from bow to stern, which is really nice because you can find a sweet spot where the boat will just feel like it is floating along on air..easy to control, and smooth.
Top speed will most likely drop a mph or two as your rpms will be down, but not enough that would make it a dog....
The best thing: mid rpm cruise. You should be able to stay on plane at a lower rpm level than you are currently finding due to the extra lift and blade. I'd guess you could still be on plane at 3000 or so rpm without too much issue (this is very tongue in cheek, though as much of this depends on what you are hauling as well...)
Worth a try, though...you might find it to be a nice improvement for what you are looking for.
Steve | |
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| Thanks for the info, Steve. I knew I could count on you for a thorough response.
Anyone else?
It's a big investment, and I don't know of a dealer with a "try it out" plan in SE Wisconsin. | |
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Posts: 270
Location: SE WISCONSIN | I don't know alot about prop's but i'm hearing alot about the spitfire prop on the 115's over at walleye central it might be worth a look. | |
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Posts: 35
| Don't know if this is ok (so delete if it is not Mods) but there is a prop shop in Brainerd, MN that will ship out a prop for you to demo for $25 + shipping. You've got two weeks, if you don't like the performance you pay for shipping back. If it's the prop for you, you've paid $25 on the price! Worked out well for me, at $400-$500 for a SS prop a guy can't afford to take a guess. Just my $.02!
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| The 17 pitch Trophy Plus is the right prop for my boat!
Max rpms right at 5900 when all trimmed out.
The biggest difference is in how the trim can now be used to adjust the attitude and performance, which was never possible with the aluminum prop.
Very nice improvement.
Edited by PJV 4/18/2014 5:10 PM
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