25' Outlaw setup tinkering
08-12-2016, 08:42 AM
#41
Gold Member
Gold Member
Do the 25's and 26's actually have a pad too?
They both have that notch but when you get underneath is there and actual pad like 6 or 8 inch or something?
They both have that notch but when you get underneath is there and actual pad like 6 or 8 inch or something?
08-12-2016, 08:54 AM
#42
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Lots of theories out there on tab mounting. Most are mounted along the V, countinuing the V hull shape. I mounted mine like this to help limit chine walk at higher speeds without having to drop the tabs much. If the boat did get into a chine walk the outside corners of the tabs should correct it when they would make contact. The only way tabs mounted along the V are going to reduce or stop chine walk is if they are dropped making full contact with the water, adding drag and reducing speed. From what I've found the go fast manufacturers that have done more testing with there hulls mount the tabs like this. Other manufacturers along the production boat lines generally have them mounted along the V because they know they work that way and don't do much testing. Not the easiest thing to explain in wording. The size of these tabs in relation to the boat also allowed me to do this, 12" tabs for example I would think would work very poorly because they don't have the reach. Many will tell me mounting them this way is silly but so far they have performed exactly as I hoped.
08-12-2016, 09:12 AM
#43
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The 25s have a long narrow pad, runs up about half the length of the boat, and a small notch. I don't believe the 26s have a notch or a pad, could be wrong tho
Last edited by IGetWet; 08-12-2016 at 09:14 AM. Reason: Correct picture
08-20-2016, 12:45 PM
#45
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I read your rebuild, looks like a nice setup. What HP do you figure with your motor? What's your propshaft height at 12" back? I imagine your prop slip numbers have to be way down
08-27-2016, 01:39 PM
#46
Registered
Picked up a 26 LH bravo 1 the other day and got good results from that. But I think a lot of it came from sanding and sharpening the lower unit. I had chipped paint etc on the lower unit and was sanding and repainting too often so I decided to take it down to bare aluminum.
After a couple short runs I calculated slip at 7.10 - 8.79% depending on exact rpm, pretty darn good for only 4.25 below the pad. My RPMs dropped because of the better grip, 67 @ 4550-4600. I did see 68 and 69 briefly on my gps but I'm using 67 and 67.5 for the prop slip calculator. The goal for now is to get setup dialed in and then add some HP next season.
After a couple short runs I calculated slip at 7.10 - 8.79% depending on exact rpm, pretty darn good for only 4.25 below the pad. My RPMs dropped because of the better grip, 67 @ 4550-4600. I did see 68 and 69 briefly on my gps but I'm using 67 and 67.5 for the prop slip calculator. The goal for now is to get setup dialed in and then add some HP next season.
08-29-2016, 05:08 PM
#47
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iTrader: (1)
Picked up a 26 LH bravo 1 the other day and got good results from that. But I think a lot of it came from sanding and sharpening the lower unit. I had chipped paint etc on the lower unit and was sanding and repainting too often so I decided to take it down to bare aluminum.
So with same power but box/raised prop cl you haven't quite matched your best speed from before any mods? That was my experience too, I put my stellings box on after talking tp a guy who claimed he had built a roots blower 850 hp baja that picked up 5 mph top speed , I have a theory, only a theory though, IF you take to 6 inch straight edges and hold them on each side of the pad on vee to form a imaginary vee the stock prop center line (mine was 7.5") is really more like 5.5" in comparison to a vee, I strongly feel thats why no matter what prop i tried and even after spacing the drive down 1" with stellings box and when I tried imco 2" shorty my 272 slowed down, would not carry the bow, porpoised etc but this was in the 90+ mph range
After a couple short runs I calculated slip at 7.10 - 8.79% depending on exact rpm, pretty darn good for only 4.25 below the pad. My RPMs dropped because of the better grip, 67 @ 4550-4600. I did see 68 and 69 briefly on my gps but I'm using 67 and 67.5 for the prop slip calculator. The goal for now is to get setup dialed in and then add some HP next season.
So with same power but box/raised prop cl you haven't quite matched your best speed from before any mods? That was my experience too, I put my stellings box on after talking tp a guy who claimed he had built a roots blower 850 hp baja that picked up 5 mph top speed , I have a theory, only a theory though, IF you take to 6 inch straight edges and hold them on each side of the pad on vee to form a imaginary vee the stock prop center line (mine was 7.5") is really more like 5.5" in comparison to a vee, I strongly feel thats why no matter what prop i tried and even after spacing the drive down 1" with stellings box and when I tried imco 2" shorty my 272 slowed down, would not carry the bow, porpoised etc but this was in the 90+ mph range
After a couple short runs I calculated slip at 7.10 - 8.79% depending on exact rpm, pretty darn good for only 4.25 below the pad. My RPMs dropped because of the better grip, 67 @ 4550-4600. I did see 68 and 69 briefly on my gps but I'm using 67 and 67.5 for the prop slip calculator. The goal for now is to get setup dialed in and then add some HP next season.
08-29-2016, 05:47 PM
#48
Registered
So with same power but box/raised prop cl you haven't quite matched your best speed from before any mods? That was my experience too, I put my stellings box on after talking tp a guy who claimed he had built a roots blower 850 hp baja that picked up 5 mph top speed , I have a theory, only a theory though, IF you take to 6 inch straight edges and hold them on each side of the pad on vee to form a imaginary vee the stock prop center line (mine was 7.5") is really more like 5.5" in comparison to a vee, I strongly feel thats why no matter what prop i tried and even after spacing the drive down 1" with stellings box and when I tried imco 2" shorty my 272 slowed down, would not carry the bow, porpoised etc but this was in the 90+ mph range
But another reason for these mods is a better rough water ride. Before the mods the boat felt like it sat more in the water at speed where now it really feels like the boat is up on top of the water riding across the tops of the waves.
Bblades got back to me today and told me that the 25 rev 4 I had bought was way out of balance, so that should answer why that specific prop did so poorly.
08-29-2016, 09:57 PM
#49
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Not sure I follow the theory, the water is coming off the pad, it doesn't follow the imaginary V. My theory on why I haven't seen any speed increase is because I went from a perfectly labbed 3 blade to a stock 4 blade. A lot more drag, weight with the four blade. If I were to have the bravo 1 labbed I should be at or above my old top speed. If the slip numbers are good then I should be able to get the speed once HP is added. Wild Card has stated more than once that he achieved 84+mph with his 600sci and 81+mph with a 525efi, good numbers for any straight bottom V!
But another reason for these mods is a better rough water ride. Before the mods the boat felt like it sat more in the water at speed where now it really feels like the boat is up on top of the water riding across the tops of the waves.
Bblades got back to me today and told me that the 25 rev 4 I had bought was way out of balance, so that should answer why that specific prop did so poorly.
But another reason for these mods is a better rough water ride. Before the mods the boat felt like it sat more in the water at speed where now it really feels like the boat is up on top of the water riding across the tops of the waves.
Bblades got back to me today and told me that the 25 rev 4 I had bought was way out of balance, so that should answer why that specific prop did so poorly.
09-03-2016, 03:05 PM
#50
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