What makes a good V-bottom?
#41
Platinum Member
Platinum Member
Carp,
If your boat is set up correctly, you don't need to props to do much other than push. Someone like Brett at BBlades would be a good source for more accurate prop input.
Look closely at the strakes in this picture. Notice that the outer strake (runs to the transom) is just in the water and the inter strake (stops about 12" behind the CG) is also just touching the water. Both just keeping the boat balanced with minimal drag. In this picture we were running over 100 MPH.
If your boat is set up correctly, you don't need to props to do much other than push. Someone like Brett at BBlades would be a good source for more accurate prop input.
Look closely at the strakes in this picture. Notice that the outer strake (runs to the transom) is just in the water and the inter strake (stops about 12" behind the CG) is also just touching the water. Both just keeping the boat balanced with minimal drag. In this picture we were running over 100 MPH.
#42
VIP Member
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This thread has been a lot of help. Thanks to everyone who chimed in.
Two questions I still haven't got answered:
1. Will raising the prop increase bow lift or decrease it?
2. What do the strakes do? they increase surface area which is bad for speed, right? but they provide lift which can be good? Do they provide any stability or resistance to chine walk? Would flattening then out at the stern help with my lack of bow lift?
Two questions I still haven't got answered:
1. Will raising the prop increase bow lift or decrease it?
2. What do the strakes do? they increase surface area which is bad for speed, right? but they provide lift which can be good? Do they provide any stability or resistance to chine walk? Would flattening then out at the stern help with my lack of bow lift?
Stakes provide both lift and stability. If they are straight and sharp, they do not add much drag.
Like I said earlier, a friend of mine had good results from removing the built in hooks on a 24.5 Formula SS.
Brett at BBlades will hook you up with the right prop. My old school straight V 24’ Super really liked the Rev 4 stock or a B1 modified for extra bow lift.
By the way, I ran my Velocity again and it's growing on me. The pad bottom does help the boat get up and go vs. a streight V. At slower speeds in waves it does hit a bit harder than at higher speeds. I'm still learning how to run it...
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Patrick
Patrick
Last edited by Pat McPherson; 07-30-2008 at 08:02 AM.
#43
On heavier V's raising the prop too much will kill bow lift, increase drag and slip. The boat will go slower.
On really light v's it takes less leverage to carry the bow.
You need to play around with it to get it right. If you have to keep the prop deep, a 3 blade will be the best option.
To get max speed out of a straight v, you have to reduce the wetted area and drag. That takes bow lift.
On really light v's it takes less leverage to carry the bow.
You need to play around with it to get it right. If you have to keep the prop deep, a 3 blade will be the best option.
To get max speed out of a straight v, you have to reduce the wetted area and drag. That takes bow lift.
#44
Registered
Thread Starter
On heavier V's raising the prop too much will kill bow lift, increase drag and slip. The boat will go slower.
On really light v's it takes less leverage to carry the bow.
You need to play around with it to get it right. If you have to keep the prop deep, a 3 blade will be the best option.
To get max speed out of a straight v, you have to reduce the wetted area and drag. That takes bow lift.
On really light v's it takes less leverage to carry the bow.
You need to play around with it to get it right. If you have to keep the prop deep, a 3 blade will be the best option.
To get max speed out of a straight v, you have to reduce the wetted area and drag. That takes bow lift.
#45
VIP Member
VIP Member
I'd say the prop shaft is at the right depth and run 4 blade props that give bow lift. Have you trie a Rev 4?
If you do make changes to the bottom, ie. grinding out those hooks, the ball game may change.
If you do make changes to the bottom, ie. grinding out those hooks, the ball game may change.
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Patrick
Patrick
#46
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Thread Starter
I think I tried a rev 4 (rev 4 is more of a cleaver looking prop right?) but it was the wrong pitch. From what I remember it seemed to drive the bow into the water even more. I didn't keep it on for long.
#47
VIP Member
VIP Member
The Bravo1 4 blade you are running is a neutral/over all lifting prop in its stock form.
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Patrick
Patrick
#48
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Thread Starter
The Merc Revolution 4 is a 4 blade version of the Mirage +. It's a round ear bow lifter and works great on old school hulls. It was the best “box stock” prop I ever ran on my 24’ Super.
The Bravo1 4 blade you are running is a neutral/over all lifting prop in its stock form.
The Bravo1 4 blade you are running is a neutral/over all lifting prop in its stock form.
Ok, that's not what I had tried. I'll try to get my hands on one to try, although, this Bravo 1 is SOOO much better than anything else I've tried, I can't imagine getting it much better until I get the bottom straight.
Nice thing is, this boat seems to love LH props, so I've been able to pick up quite a few for pretty cheep since there's always someone else that wants the RH mate.
#49
Registered
Ok, that's not what I had tried. I'll try to get my hands on one to try, although, this Bravo 1 is SOOO much better than anything else I've tried, I can't imagine getting it much better until I get the bottom straight.
Nice thing is, this boat seems to love LH props, so I've been able to pick up quite a few for pretty cheep since there's always someone else that wants the RH mate.
Nice thing is, this boat seems to love LH props, so I've been able to pick up quite a few for pretty cheep since there's always someone else that wants the RH mate.
That was my Rev4 that pat tried. They have a lot of rake so they really carry the bow well. I've tried a lot of props on my boat and it's still my favorite. Handles way better than a stock Bravo on my boat.
But I still say you should be running faster with the hp you have.
#50
Registered
Carp,
I agree with Jim, you could get the boat to run 90-100+ MPH but today most of your set-up is not for top speed. To get significantly more speed, it will take major changes that are not in the engine compartment. My 1987 Scarab will run over 100 MPH but I could buy a new 39' Outerlimits with twin 1075's for less than I have spend over the last 20 years clawing up the wall.
Ben
I agree with Jim, you could get the boat to run 90-100+ MPH but today most of your set-up is not for top speed. To get significantly more speed, it will take major changes that are not in the engine compartment. My 1987 Scarab will run over 100 MPH but I could buy a new 39' Outerlimits with twin 1075's for less than I have spend over the last 20 years clawing up the wall.
Ben
Dude .....the truth hurts .....shhhhhhh .......