Props turning outword vs. inword
01-21-2003, 07:17 AM
#2
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if you turn your props inward you get more bow lift. <-- correction
Some hulls react better to inward whereas other might loose soem speed and handle like carp. If you haev bravos its easy to try. Just put your port prop on eth starbaord drive and vice versa and then just remeber taht our shift levers are backward (f is R and r is F). If it works well on your hull you can easily change the shift levers. YOu might even pickup some speed out o it. Or perhaps just get better handling.
Some hulls react better to inward whereas other might loose soem speed and handle like carp. If you haev bravos its easy to try. Just put your port prop on eth starbaord drive and vice versa and then just remeber taht our shift levers are backward (f is R and r is F). If it works well on your hull you can easily change the shift levers. YOu might even pickup some speed out o it. Or perhaps just get better handling.
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Last edited by puder; 01-23-2003 at 01:32 AM.
01-21-2003, 09:19 AM
#3
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My experiences, and from voices of
others.
Turning the props in (port R/H rot.
starboard L/H rot.) will carry the
bow, or in other term's, bow lift.
Turning out, stern lift.
I have always equated this based on
the swing of the prop in respect to the
chine side of the drives.
When turning in, the blades are on the
upswing, and "digging in", giving the
drives more leverage to carry the nose.
When turning out, blades are on the down swing,
" paddlewheeling" in effect, creating lift at the drives,
causing stern lift
The props aren't running as deep on the keel
side of the drive, due to the void the vee creates,
so that portion of the blades rotation has less
leverage.
Some boats benefit from inward rotation,
some don't, with bravo drive's, it's easy to try,
switch the props around and run the shifters
opposite.
One thing I always have found true about
inward rotation is, when manuevering around the
docks, handling is poorer, whichever drive is in
reverse seems to have very little leverage.
my .02
jt
others.
Turning the props in (port R/H rot.
starboard L/H rot.) will carry the
bow, or in other term's, bow lift.
Turning out, stern lift.
I have always equated this based on
the swing of the prop in respect to the
chine side of the drives.
When turning in, the blades are on the
upswing, and "digging in", giving the
drives more leverage to carry the nose.
When turning out, blades are on the down swing,
" paddlewheeling" in effect, creating lift at the drives,
causing stern lift
The props aren't running as deep on the keel
side of the drive, due to the void the vee creates,
so that portion of the blades rotation has less
leverage.
Some boats benefit from inward rotation,
some don't, with bravo drive's, it's easy to try,
switch the props around and run the shifters
opposite.
One thing I always have found true about
inward rotation is, when manuevering around the
docks, handling is poorer, whichever drive is in
reverse seems to have very little leverage.
my .02
jt
01-21-2003, 09:49 AM
#4
Charter Member #30
Charter Member
Spinning in with Bravo props should give you bow lift. Pulling the stern down. This is a tried fact on my boat and not a guess!
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01-21-2003, 12:46 PM
#8
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Steve,
friends of mine have a Donzi 33zx,
(they have actually owned 2)
both of these boats came with
props rotation inward, although
I have seen, both 38's and 28's
with outside rotation.
Gary,
I've heard that too,
my guess is the that the inside
of the drives are running deeper
due to clean flow of water coming
between the sponsons, and the drives
are usually placed closer to the inside
of the sponsons.
jt.
friends of mine have a Donzi 33zx,
(they have actually owned 2)
both of these boats came with
props rotation inward, although
I have seen, both 38's and 28's
with outside rotation.
Gary,
I've heard that too,
my guess is the that the inside
of the drives are running deeper
due to clean flow of water coming
between the sponsons, and the drives
are usually placed closer to the inside
of the sponsons.
jt.
01-21-2003, 01:27 PM
#9
Charter Member #30
Charter Member
Quest for Speed,
I tried to spin mine out and lost about 5mph or more and had a huge rooster tail. I read your post over in PQ but you never posted your power. Our hulls have had a history of not working well spinning out and many other stepped hulls are also spinning in. If you want my opinions on the hull and what works I can answer it over in the other forum. I don't want to take away from BETTERTON's post.
I'd also like to add that the type of prop has a lot to do with this a Hydromotive gives stern lift and a Bravo is better for bow lift. This is what the manufacture told me and also info that was given to me from Hydromotive.
Spinning in on a stepped hull,
This is a huge can of worms and will come up with a lot of different opinions. I can only speak for my set-up and can say that it feels very stable in all kinds of water and holds tight even in the "oh SH*#t there's a jet ski" type turn! I strongly believe and practice that the stepped hull requires different trim angles for stable and safe handling. I am guessing that some stepped boats mixed with a bad design and a uneducated user with the wrong set-up could lead to disaster. That is the reason the spinning in issue is so sensitive. Like I said I've never had a problem and feel that my boat is safe and stable with the props spinning in would It feel even safer spinning out? probably would
Would it be a slow, prop slipping,rooster tail slinging lead sled? Absolutely
I tried to spin mine out and lost about 5mph or more and had a huge rooster tail. I read your post over in PQ but you never posted your power. Our hulls have had a history of not working well spinning out and many other stepped hulls are also spinning in. If you want my opinions on the hull and what works I can answer it over in the other forum. I don't want to take away from BETTERTON's post.
I'd also like to add that the type of prop has a lot to do with this a Hydromotive gives stern lift and a Bravo is better for bow lift. This is what the manufacture told me and also info that was given to me from Hydromotive.
Spinning in on a stepped hull,
This is a huge can of worms and will come up with a lot of different opinions. I can only speak for my set-up and can say that it feels very stable in all kinds of water and holds tight even in the "oh SH*#t there's a jet ski" type turn! I strongly believe and practice that the stepped hull requires different trim angles for stable and safe handling. I am guessing that some stepped boats mixed with a bad design and a uneducated user with the wrong set-up could lead to disaster. That is the reason the spinning in issue is so sensitive. Like I said I've never had a problem and feel that my boat is safe and stable with the props spinning in would It feel even safer spinning out? probably would
Would it be a slow, prop slipping,rooster tail slinging lead sled? Absolutely
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I have Steps & Bubbles!
I have Steps & Bubbles!
