Bad list at speed?
08-25-2002, 11:07 AM
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Bad list at speed?
My 42 Sonic just started lising to starboard to the point that it's getting kinda scary at speed. I can find no obvious cause. Any ideas anyone?
08-25-2002, 11:13 AM
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Sean said to check your tabs and see if they are in sync with your indicators and also to do the same with the drives. Also do you have more than one fuel tank? If so make sure that they are the same level in both sides if applicable. Also do same with any other tanks he said. Get back with more info if needed.
08-25-2002, 04:18 PM
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Madcow a friend had a similar problem when I drove the boat the throttles tried to heel the boat over slightly everything else was in order, There was no trapped water and I set the trim at the Ramp to be sure.
Turns out one of the Propellers was the culprit! You would be surprised at the stern lift ! Here is the Problem in the US with propellers !In a Nutshell!
ISO 484/2 is a classification system set up by the International Standards Organization for the Repair and Manufacture of Ship's Screw Propellers.
While the U.S. is not a signatory to this particular standard it none-the-less, allows us A tool to discuss the quality of the propellers.
ISO defines four different classes of propellers. Class 3 which is defined as a Low Accuracy Propeller where the mean measured pitch of the blades have to be within 4% of each other. Class 2 is defined as a Medium Accuracy Propeller where the pitch of the blades must be within 1.5% of the other blades. Class 1 is a High Accuracy Propeller, blade pitch must be within 1%. Finally, Class S, which is a Very High Accuracy Propeller with pitches within 0.75% of each other.
Most propellers are Class 3 or worse. We regularly see pitch variances between blades of a single propeller and between propellers on twin screw vessels of as much as _3/4". This means that there can be as much as 1 1/2" of total pitch difference between two propellers!
So you see it is kind of Wild West here in the States In some cases! Make sure whoever does the props has Prop Scan or the Equivalent to check with !
Turns out one of the Propellers was the culprit! You would be surprised at the stern lift ! Here is the Problem in the US with propellers !In a Nutshell!
ISO 484/2 is a classification system set up by the International Standards Organization for the Repair and Manufacture of Ship's Screw Propellers.
While the U.S. is not a signatory to this particular standard it none-the-less, allows us A tool to discuss the quality of the propellers.
ISO defines four different classes of propellers. Class 3 which is defined as a Low Accuracy Propeller where the mean measured pitch of the blades have to be within 4% of each other. Class 2 is defined as a Medium Accuracy Propeller where the pitch of the blades must be within 1.5% of the other blades. Class 1 is a High Accuracy Propeller, blade pitch must be within 1%. Finally, Class S, which is a Very High Accuracy Propeller with pitches within 0.75% of each other.
Most propellers are Class 3 or worse. We regularly see pitch variances between blades of a single propeller and between propellers on twin screw vessels of as much as _3/4". This means that there can be as much as 1 1/2" of total pitch difference between two propellers!
So you see it is kind of Wild West here in the States In some cases! Make sure whoever does the props has Prop Scan or the Equivalent to check with !
Last edited by Steve 1; 08-25-2002 at 04:21 PM.
08-25-2002, 05:33 PM
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Boats always list into the wind (never understood why) and it's far more pronounced at the higher speeds when less boat is in the water. It's also more noticable on high freeboard boats like Sonics.
Does it list the other way if you turn around?
Does it list the other way if you turn around?
08-25-2002, 07:56 PM
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Originally posted by Ron P
Boats always list into the wind (never understood why) and it's far more pronounced at the higher speeds when less boat is in the water. It's also more noticable on high freeboard boats like Sonics...
Boats always list into the wind (never understood why) and it's far more pronounced at the higher speeds when less boat is in the water. It's also more noticable on high freeboard boats like Sonics...
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Retired! Boating full-time now.
08-25-2002, 08:44 PM
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Originally posted by C_Spray
Ron - Here's how a certain Swedish (lawn-dart) designer explained it to me: The wind tries to push the front of the boat off downwind, so you counter-steer into the wind. Therefore, you are effectively "turning" (hence the heel into the wind), but the wind keeps you going in a straight line. Make sense?
Ron - Here's how a certain Swedish (lawn-dart) designer explained it to me: The wind tries to push the front of the boat off downwind, so you counter-steer into the wind. Therefore, you are effectively "turning" (hence the heel into the wind), but the wind keeps you going in a straight line. Make sense?
