Surface drives...
11-04-2002, 08:40 AM
#1
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Surface drives...
Anyone use this type of drive. I have a Cafe and am considering dumping the damm Bravo's and going with the Pulse Drive. Any info on any type of surface pericing drive system would help (Arenson, Trimax, etc.).
Mongo
Mongo
11-06-2002, 07:13 AM
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1975 X-18 Donzi, Arneson
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The fin helps give bow lift. It depends on your boat. Some boat's designs have good bow lift built in. Some bow lift; ie. cat's & tunnel's, is created with the help of the air flow around the hull.
Outboard boat's play with the CG and move the engine back to create more bow lift.
The faster you go the more lift the stern, (prop, outdrive) will have and the more bow lift you will need to counter the stern lift to balance the boat.
The "fin" helps neutralize the effects of the prop& drive lift.
My boat would run fine at 60mph above that it created to much stern lift and the fin is needed.
Outboard boat's play with the CG and move the engine back to create more bow lift.
The faster you go the more lift the stern, (prop, outdrive) will have and the more bow lift you will need to counter the stern lift to balance the boat.
The "fin" helps neutralize the effects of the prop& drive lift.
My boat would run fine at 60mph above that it created to much stern lift and the fin is needed.
Last edited by GEOO; 11-06-2002 at 02:10 PM.
11-06-2002, 08:12 AM
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Location: N41 41.709' - W93 41.916'
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And when you say to much stern lift .. you would loose speed? or the boat would get loose? We have Arneson’s rocker plates so I’m hoping the rocker will keep the stern down for us.
And again I’m looking at your photo. What’s your speed and RPM’s in that shot?
And again I’m looking at your photo. What’s your speed and RPM’s in that shot?
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11-06-2002, 02:03 PM
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1975 X-18 Donzi, Arneson
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D_Casten,
If the bow doesn't ride high enough, then you'll run into bow steer. The lower fin will add more appendage drag, but you gain speed and controllablity. by having less wetted surface. You can try it without the fin and if you need more bow lift then add the fin, that's what I did. It all depends on your boat set up and speeds you'll be running.
What size boat? Weight? HP? Type of speed??
Rik, is great at helping you set up the boat.
If the bow doesn't ride high enough, then you'll run into bow steer. The lower fin will add more appendage drag, but you gain speed and controllablity. by having less wetted surface. You can try it without the fin and if you need more bow lift then add the fin, that's what I did. It all depends on your boat set up and speeds you'll be running.
What size boat? Weight? HP? Type of speed??
Rik, is great at helping you set up the boat.
Last edited by GEOO; 11-06-2002 at 02:09 PM.
11-06-2002, 04:16 PM
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It’s a 26ft Crownline that weighs 5,000lbs, 454mag with a Whipple. We cut the hook out of the hull and added the Arneson rocker plates. We’re only getting 65mph out of the boat because of a real low X dem. So the bravo conversion kit would make that a mute point. Along with the speed I’m hoping for a better ride and to make use of the rockers.
