Boat not stable with new motor at top speed
10-13-2003, 09:06 AM
#13
Platinum Member
Platinum Member
Mmkay,
With 13% slip, you're going 64. We can work with you here.
#1) Are you running external steering?
#2) Do you have a trim gauge?
#3) Do you have any tabs at all?
#4) Where is your fuel tank(s) located?
#5) Do you have a freshwater system for a sink, etc.?
If you are NOT running ext steering, you need to check the condition and slop in all gimbal and steering components all the way to the helm. Any play or wear in these components will make it difficult to properly control the boat.
If you have a trim gauge, take note of the reading on the trim gauge when the drive is parallel to the running surface of the boat. This is "neutral" trim. You will need to reference the trim position to us when you describe your boat's behavior.
If you have tabs, please make all baseline runs with the tabs in the full UP position. While tabs can be used to moderate any weirdness, they are a bandaid, not an answer. Tabs are wonderful, but you must begin with a hull to power setup that behaves in smooth water first.
If your fuel tank is located on the centerline of the boat, then fuel load will not cause side imbalances. many times, however, fuel tanks are not properly baffled for high performance use. If you run less than a full tank, sloshing could be intensifying any issues you may be encountering. Do all baseline runs with a completely full load of fuel to minimize any sloshing tendencies. If you have more than one tank, let us know and we can use that knowledge for ballasting suggestions.
If you have a freshwater system, pump it dry for these baseline runs. Sloshing and weight on the bow will be removed from the equation.
Now, we need better description of the problem.
Take care of the above stuff. Plane out, raise tabs, put trim at neutral and note the speed at which the boat begins acting oddly. Tell us at what speed and how it feels and acts. Go a bit faster and tell us what that does. If you can get the boat to WOT at neutral trim with no oddness, then this tells us a lot. If you can do so, then do it and take note of it. Begin trimming up a little at a time and take note of speed at each position and note where when and how the boat feels when it begins to get weird.
We'll get this figured out.
Hopefully, it is a weight distribution issue. It may be a host of other things though.
With 13% slip, you're going 64. We can work with you here.
#1) Are you running external steering?
#2) Do you have a trim gauge?
#3) Do you have any tabs at all?
#4) Where is your fuel tank(s) located?
#5) Do you have a freshwater system for a sink, etc.?
If you are NOT running ext steering, you need to check the condition and slop in all gimbal and steering components all the way to the helm. Any play or wear in these components will make it difficult to properly control the boat.
If you have a trim gauge, take note of the reading on the trim gauge when the drive is parallel to the running surface of the boat. This is "neutral" trim. You will need to reference the trim position to us when you describe your boat's behavior.
If you have tabs, please make all baseline runs with the tabs in the full UP position. While tabs can be used to moderate any weirdness, they are a bandaid, not an answer. Tabs are wonderful, but you must begin with a hull to power setup that behaves in smooth water first.
If your fuel tank is located on the centerline of the boat, then fuel load will not cause side imbalances. many times, however, fuel tanks are not properly baffled for high performance use. If you run less than a full tank, sloshing could be intensifying any issues you may be encountering. Do all baseline runs with a completely full load of fuel to minimize any sloshing tendencies. If you have more than one tank, let us know and we can use that knowledge for ballasting suggestions.
If you have a freshwater system, pump it dry for these baseline runs. Sloshing and weight on the bow will be removed from the equation.
Now, we need better description of the problem.
Take care of the above stuff. Plane out, raise tabs, put trim at neutral and note the speed at which the boat begins acting oddly. Tell us at what speed and how it feels and acts. Go a bit faster and tell us what that does. If you can get the boat to WOT at neutral trim with no oddness, then this tells us a lot. If you can do so, then do it and take note of it. Begin trimming up a little at a time and take note of speed at each position and note where when and how the boat feels when it begins to get weird.
We'll get this figured out.
Hopefully, it is a weight distribution issue. It may be a host of other things though.
10-13-2003, 09:10 AM
#14
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Gary C,
PQ calls them wedges, some people call them hooks. They extend forward from the transom forward for about 12". What happens on glass smooth water at higher speeds (>65) is neither side is touching the water and then one side touches and bounces the boat over to the other side. I found that the 260 needed more bow lift and the mirage plus did a much better job than a bravo one. On choppy water you will not see nearly as much.
PQ calls them wedges, some people call them hooks. They extend forward from the transom forward for about 12". What happens on glass smooth water at higher speeds (>65) is neither side is touching the water and then one side touches and bounces the boat over to the other side. I found that the 260 needed more bow lift and the mirage plus did a much better job than a bravo one. On choppy water you will not see nearly as much.
10-13-2003, 11:32 AM
#15
OSO Moderator
Charter Member
I agree, try a Bravo 1 prop.
__________________
BillR
'00 Scarab Sport 302 CC
'02 Cigarette Top Gun TS
'02 PQ 340
'00 PQ 280
'98 Scarab 22
'97 Baja Outlaw 20
'72 Checkmate
'65 Glastron
BillR
'00 Scarab Sport 302 CC
'02 Cigarette Top Gun TS
'02 PQ 340
'00 PQ 280
'98 Scarab 22
'97 Baja Outlaw 20
'72 Checkmate
'65 Glastron
10-13-2003, 12:35 PM
#16
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Originally posted by GEOO
That doesn't sound overpowered to me.
Sound's like a set-up issue.
That doesn't sound overpowered to me.
Sound's like a set-up issue.
GEOO - NOTHING ever sounds over-powered to you, but then you're a nutcase......
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Retired! Boating full-time now.
Retired! Boating full-time now.
10-13-2003, 01:44 PM
#17
Registered
rbtnt,
I also found that a Mirage plus is the best prop for a 260 I had my 21 turned to a 22. I'm still on the limiter. I'm gonna try a 23 next year. I hardly ever see flat water.
pkxps,
I would try a 23 Mirage plus on your boat. I think you will like it a lot better. You should spin it about the same as your Hydro. If you gotta have a 4 blade try a 24 Bravo 1 That should be around 5100 rpms. You do need bow lift on that boat.
I also found that a Mirage plus is the best prop for a 260 I had my 21 turned to a 22. I'm still on the limiter. I'm gonna try a 23 next year. I hardly ever see flat water.
pkxps,
I would try a 23 Mirage plus on your boat. I think you will like it a lot better. You should spin it about the same as your Hydro. If you gotta have a 4 blade try a 24 Bravo 1 That should be around 5100 rpms. You do need bow lift on that boat.
