26 spline 4 blade
Platinum Member
10-05-2012, 06:25 PM
#2
Registered
I believe I have a pair of 3 blade 26 pitch Merc Mirage props. I will have to check my garage tomorrow. Would you be interested?
I went to 28 four blades after a power increase.
I went to 28 four blades after a power increase.
10-06-2012, 07:40 AM
#4
Registered
iTrader: (3)
Hey Frank, just food for thought. Im running IVs on my 38 Straight bottom Fountain. I will share some of my results.
17x29p Four blades. 5600RPM, 84mph. Very slow to plane.
17x28p Four blades, cup added at mercury. 5600RPM, 88MPH. Plane much better.
Also, I tried a set of 16.5x28 5 blades last year. Planed off perfect. No slip at all getting up. Problem at that time, wasnt making the HP, and couldnt turn them past 4700, so sold them.
Tried a couple other sets, and from what I have found, is there are so many inconsistancies with the old ssm props, there isnt much rhyme or reason. One set of props can slip like holy hell, and another identical stamped props can be fantastic.
One set of 4 blades I tried, would not get the boat on plane period. 5000RPM burnouts, nothing. Then bolted another set on, planed like a ski boat. I guess what Im getting at, is cupping is where its at with these props. If the blades cant hold water, they slip to all hell.
Compared a set of 17 1/8 diameter to a set of 16 7/8 diameter four blades, believe it or not the small diameter set planed worlds better. According to the prop scan on these two sets, the smaller diamter had cupping in the .070-.080 range, the larger diameter in the .030-050 range.
Not saying 18'' props wont help you, just sharing my experiance.
17x29p Four blades. 5600RPM, 84mph. Very slow to plane.
17x28p Four blades, cup added at mercury. 5600RPM, 88MPH. Plane much better.
Also, I tried a set of 16.5x28 5 blades last year. Planed off perfect. No slip at all getting up. Problem at that time, wasnt making the HP, and couldnt turn them past 4700, so sold them.
Tried a couple other sets, and from what I have found, is there are so many inconsistancies with the old ssm props, there isnt much rhyme or reason. One set of props can slip like holy hell, and another identical stamped props can be fantastic.
One set of 4 blades I tried, would not get the boat on plane period. 5000RPM burnouts, nothing. Then bolted another set on, planed like a ski boat. I guess what Im getting at, is cupping is where its at with these props. If the blades cant hold water, they slip to all hell.
Compared a set of 17 1/8 diameter to a set of 16 7/8 diameter four blades, believe it or not the small diameter set planed worlds better. According to the prop scan on these two sets, the smaller diamter had cupping in the .070-.080 range, the larger diameter in the .030-050 range.
Not saying 18'' props wont help you, just sharing my experiance.
10-06-2012, 08:14 AM
#5
Hey Frank, just food for thought. Im running IVs on my 38 Straight bottom Fountain. I will share some of my results.
17x29p Four blades. 5600RPM, 84mph. Very slow to plane.
17x28p Four blades, cup added at mercury. 5600RPM, 88MPH. Plane much better.
Also, I tried a set of 16.5x28 5 blades last year. Planed off perfect. No slip at all getting up. Problem at that time, wasnt making the HP, and couldnt turn them past 4700, so sold them.
Tried a couple other sets, and from what I have found, is there are so many inconsistancies with the old ssm props, there isnt much rhyme or reason. One set of props can slip like holy hell, and another identical stamped props can be fantastic.
One set of 4 blades I tried, would not get the boat on plane period. 5000RPM burnouts, nothing. Then bolted another set on, planed like a ski boat. I guess what Im getting at, is cupping is where its at with these props. If the blades cant hold water, they slip to all hell.
Compared a set of 17 1/8 diameter to a set of 16 7/8 diameter four blades, believe it or not the small diameter set planed worlds better. According to the prop scan on these two sets, the smaller diamter had cupping in the .070-.080 range, the larger diameter in the .030-050 range.
Not saying 18'' props wont help you, just sharing my experiance.
17x29p Four blades. 5600RPM, 84mph. Very slow to plane.
17x28p Four blades, cup added at mercury. 5600RPM, 88MPH. Plane much better.
Also, I tried a set of 16.5x28 5 blades last year. Planed off perfect. No slip at all getting up. Problem at that time, wasnt making the HP, and couldnt turn them past 4700, so sold them.
Tried a couple other sets, and from what I have found, is there are so many inconsistancies with the old ssm props, there isnt much rhyme or reason. One set of props can slip like holy hell, and another identical stamped props can be fantastic.
One set of 4 blades I tried, would not get the boat on plane period. 5000RPM burnouts, nothing. Then bolted another set on, planed like a ski boat. I guess what Im getting at, is cupping is where its at with these props. If the blades cant hold water, they slip to all hell.
Compared a set of 17 1/8 diameter to a set of 16 7/8 diameter four blades, believe it or not the small diameter set planed worlds better. According to the prop scan on these two sets, the smaller diamter had cupping in the .070-.080 range, the larger diameter in the .030-050 range.
Not saying 18'' props wont help you, just sharing my experiance.
Gold Member
