removing 2" spacer need opinions
06-07-2016, 09:43 AM
#1
Registered
Thread Starter
Join Date: Aug 2015
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
removing 2" spacer need opinions
considering removing 2" spacer on SSM lV's to put bullet even with bottom of boat, currently plans easily at 3k with 16.5 x 28 4 blades, what effect will higher X have on planning, mid range cruising and top end, boat is 89 straight bottom full cabin side by side Top Gun
Thanks
Moxy
Thanks
Moxy
06-07-2016, 10:30 AM
#2
Registered
Moxy,
I have a similar setup you are thinking about doing. From my experience, you will not be able to plane with those props (or it may be extremely aggravating), which may be a problem down the road on top end depending on how much power you are making. My boat may be different, but it will definitely affect it.
I would assume your cruise and top end would increase, how much I cannot say (2-3 mph, all else being equal?).
Fyi, I am running even to bottom with 17.5" dia props, and it's not a cake walk to get on plane. Maybe you should try a 1" spacer first to see how you like it?
I have a similar setup you are thinking about doing. From my experience, you will not be able to plane with those props (or it may be extremely aggravating), which may be a problem down the road on top end depending on how much power you are making. My boat may be different, but it will definitely affect it.
I would assume your cruise and top end would increase, how much I cannot say (2-3 mph, all else being equal?).
Fyi, I am running even to bottom with 17.5" dia props, and it's not a cake walk to get on plane. Maybe you should try a 1" spacer first to see how you like it?
Last edited by frickstyle; 06-07-2016 at 10:41 AM.
06-07-2016, 11:06 AM
#3
Registered
Thread Starter
Join Date: Aug 2015
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
Moxy,
I have a similar setup you are thinking about doing. From my experience, you will not be able to plane with those props (or it may be extremely aggravating), which may be a problem down the road on top end depending on how much power you are making. My boat may be different, but it will definitely affect it.
I would assume your cruise and top end would increase, how much I cannot say (2-3 mph, all else being equal?).
Fyi, I am running even to bottom with 17.5" dia props, and it's not a cake walk to get on plane. Maybe you should try a 1" spacer first to see how you like it?
I have a similar setup you are thinking about doing. From my experience, you will not be able to plane with those props (or it may be extremely aggravating), which may be a problem down the road on top end depending on how much power you are making. My boat may be different, but it will definitely affect it.
I would assume your cruise and top end would increase, how much I cannot say (2-3 mph, all else being equal?).
Fyi, I am running even to bottom with 17.5" dia props, and it's not a cake walk to get on plane. Maybe you should try a 1" spacer first to see how you like it?
Thanks
Moxy
06-07-2016, 05:23 PM
#4
Registered
Icdeppl has IV's on boxes on a 38 Flatdeck. His boat originally came with 17.5x28 five blades, no spacers, and propshafts around even or a little above the bottom, I cant remember now. First run with the boat, water was a bit choppy. Took FOREVER to get on plane. 5,0000rpm burnout for 1/2 a mile. He installed 2 inch spacers, didn't help much at all. Still a huge burnout , and took forever. He then got a set of 17.5"x27 four blades, that were straight from mercury racing with lab finish, unmolested props. Boat planed off in seconds at about 2800rpm, almost zero prop slip. Then, seeing how well it planed with these props, he removed the 2 inch spacers, and the boat still planed very well.
My 38 Fountain with #4's has been very similar in reacting. Somehow the interweb has been filled with "diameter" is what you need to get on plane, as if it is the only thing that matters for getting on plane. I have found zero substance in that, in the 3 or 4 SSM boats I have played with. I have had 16 3/4 diameter 4 blades, plane better than 17+inch five blades, 18 inch 3 blades, plane better than 17.5" four blades. I had 16.5x27 four blades on my fountain that hooked up so well, I could basically pop the boat on plane, and give it all the throttle I wanted, with no blowing out. My current 17x28 props, I have to feather the throttle to keep from hitting the rev limiters getting on plane.
Getting on plane is first part of the battle. Then you have to figure out if your boat needs diameter , rake, more or less blades, round ear or cleavers, and so on. none of it matters though if you cant get on plane.
Most of these old SSM props are molested, repaired, modified, and so on. If you get a good set of props, I suggest hangin on to them!
My 38 Fountain with #4's has been very similar in reacting. Somehow the interweb has been filled with "diameter" is what you need to get on plane, as if it is the only thing that matters for getting on plane. I have found zero substance in that, in the 3 or 4 SSM boats I have played with. I have had 16 3/4 diameter 4 blades, plane better than 17+inch five blades, 18 inch 3 blades, plane better than 17.5" four blades. I had 16.5x27 four blades on my fountain that hooked up so well, I could basically pop the boat on plane, and give it all the throttle I wanted, with no blowing out. My current 17x28 props, I have to feather the throttle to keep from hitting the rev limiters getting on plane.
Getting on plane is first part of the battle. Then you have to figure out if your boat needs diameter , rake, more or less blades, round ear or cleavers, and so on. none of it matters though if you cant get on plane.
Most of these old SSM props are molested, repaired, modified, and so on. If you get a good set of props, I suggest hangin on to them!
06-07-2016, 05:37 PM
#5
Registered
Thread Starter
Join Date: Aug 2015
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
Icdeppl has IV's on boxes on a 38 Flatdeck. His boat originally came with 17.5x28 five blades, no spacers, and propshafts around even or a little above the bottom, I cant remember now. First run with the boat, water was a bit choppy. Took FOREVER to get on plane. 5,0000rpm burnout for 1/2 a mile. He installed 2 inch spacers, didn't help much at all. Still a huge burnout , and took forever. He then got a set of 17.5"x27 four blades, that were straight from mercury racing with lab finish, unmolested props. Boat planed off in seconds at about 2800rpm, almost zero prop slip. Then, seeing how well it planed with these props, he removed the 2 inch spacers, and the boat still planed very well.
My 38 Fountain with #4's has been very similar in reacting. Somehow the interweb has been filled with "diameter" is what you need to get on plane, as if it is the only thing that matters for getting on plane. I have found zero substance in that, in the 3 or 4 SSM boats I have played with. I have had 16 3/4 diameter 4 blades, plane better than 17+inch five blades, 18 inch 3 blades, plane better than 17.5" four blades. I had 16.5x27 four blades on my fountain that hooked up so well, I could basically pop the boat on plane, and give it all the throttle I wanted, with no blowing out. My current 17x28 props, I have to feather the throttle to keep from hitting the rev limiters getting on plane.
Getting on plane is first part of the battle. Then you have to figure out if your boat needs diameter , rake, more or less blades, round ear or cleavers, and so on. none of it matters though if you cant get on plane.
Most of these old SSM props are molested, repaired, modified, and so on. If you get a good set of props, I suggest hangin on to them!
My 38 Fountain with #4's has been very similar in reacting. Somehow the interweb has been filled with "diameter" is what you need to get on plane, as if it is the only thing that matters for getting on plane. I have found zero substance in that, in the 3 or 4 SSM boats I have played with. I have had 16 3/4 diameter 4 blades, plane better than 17+inch five blades, 18 inch 3 blades, plane better than 17.5" four blades. I had 16.5x27 four blades on my fountain that hooked up so well, I could basically pop the boat on plane, and give it all the throttle I wanted, with no blowing out. My current 17x28 props, I have to feather the throttle to keep from hitting the rev limiters getting on plane.
Getting on plane is first part of the battle. Then you have to figure out if your boat needs diameter , rake, more or less blades, round ear or cleavers, and so on. none of it matters though if you cant get on plane.
Most of these old SSM props are molested, repaired, modified, and so on. If you get a good set of props, I suggest hangin on to them!
Thanks for the info again,
Moxy
06-07-2016, 05:46 PM
#6
Registered
thanks for the info, these appear to be a nice pair of cupped 16 5/8 x 28 merc labbed 4 blades that b blades has massaged bought from OSO member, 3 blade 17 x 28 merc cleavers needed extended 4K run to plane of with a lot of difficulty, these 4 blades at 2800 to 3000 plane with minor cavitation but relatively easy, so I intended to raise drives looking for efficiency and mid range cruising ease. But ill definitely keep these until I fine another set that perform as well, I may have missed on the pitch, I can take these over 5500 with ease so i'm thinking there may be a set of 30's in my future
Thanks for the info again,
Moxy
Thanks for the info again,
Moxy
06-07-2016, 06:33 PM
#8
Registered
When I had my 1993 Top Gun with 875HP and 3A drives, the X dimension was moved up twice to run like 5s. It was 5/8" above the bottom when done. I didnt have trouble planning at about 3200 RPM. I had 17.75x 32 wheels. Diameter is the key, not the spacers. As soon as you have labbing, fix a ding, or even get polished you loose diameter which is critical in getting you out of the hole.
06-07-2016, 07:54 PM
#9
Registered
Thread Starter
Join Date: Aug 2015
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
When I had my 1993 Top Gun with 875HP and 3A drives, the X dimension was moved up twice to run like 5s. It was 5/8" above the bottom when done. I didnt have trouble planning at about 3200 RPM. I had 17.75x 32 wheels. Diameter is the key, not the spacers. As soon as you have labbing, fix a ding, or even get polished you loose diameter which is critical in getting you out of the hole.
Moxy
06-07-2016, 08:03 PM
#10
Registered
Thread Starter
Join Date: Aug 2015
Posts: 129
Likes: 0
Received 0 Likes
on
0 Posts
When I had my 1993 Top Gun with 875HP and 3A drives, the X dimension was moved up twice to run like 5s. It was 5/8" above the bottom when done. I didnt have trouble planning at about 3200 RPM. I had 17.75x 32 wheels. Diameter is the key, not the spacers. As soon as you have labbing, fix a ding, or even get polished you loose diameter which is critical in getting you out of the hole.
Moxy
