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Spiker 1200hp 460
- Thread starter Coolerman
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spiker
New member
Waiting on exhaust, had to order another hatch actuator, bolt on drives, install pin cleats, wire genset and put it in the water.
Had some family issues to attend to the last several months in between a work trip to Argentina for 10 days, now back and working on it most every night and on weekends until its done.
Coolerman
Charter Member
Depends if you are spinning in or out..... If you spin in, the drives want to pull themselves together, so you toe them out. If you spin out, the drives pull themselves apart and you should toe in just a bit. I'm not sure on the exact measurements..... Maybe a 1/4"? Don't quote me on that one though. The toe in/out is also dependent upon how much power the boat has.
Are you going to spin them in with a hering 6 blade?
Are you going to spin them in with a hering 6 blade?
Ratickle
Founding Member / Super Moderator
From Bob Teague in an old Powerboat Magazine
TOE-IN OR OUT?
QUESTION: Can you explain the correct procedure for setting the drive alignment on a twin-engine boat? I would think that if they are not in correct alignment, you could be scrubbing speed.
On a car, there is a certain amount of toe-in, and when the car starts moving, that position will change. Is a boat the same? Does the procedure change with regard to the direction the props are turning?
ANSWER: Traditionally, the front suspension on an automobile is set up so the wheels have a slight amount of toe-in. Being that there is (probably more in the old days) a certain amount of slop or play in the suspension or steering components such as ball joints, drag links, bushings and so on, if the front wheels were not set slightly toed-in to keep a constant load in one direction, the result would be what is called a shimmy. A shimmy can lead to a violent shaking of the front wheels and the steering wheel.
The amount the drives should be toed-in or toed-out on a boat depends on a number of factors. The most common considerations are hull type, drive type, propeller shaft depth and propeller rotation.
Generally speaking, twin-engine V-bottom boats with the propellers spinning out are usually set up with the drives toed-in slightly. It is common to set the nose of the drives about 1/8-inch closer together than the aft end of the prop shafts. The theory is that water exiting from the back of the hull is being parted slightly by the keel, so setting the drives at a slightly toed-in angle would result in them running more aligned with the water flow. That is only a theory. What we do know is that certain boats handle better with varying degrees of drive toe-in or toe-out.
If the propeller shafts are high enough so the propellers are surfacing, the side load created by the propeller blades seeing cleaner water in the lower sweep of their rotation will tend to push the drive in one direction. Similar to an automobile suspension, there is a slight amount of play in the gimbal ring and transom assembly pins and attachments.
The side force created by a surfacing propeller will load the drive and transom assembly in the opposite direction of the propeller rotation. In other words, if the propeller is a right-hand rotation (clockwise from the rear), the result is that the force is the same as turning (or flexing) the drive to the right, and vice versa.
If your propellers are surfacing and turning out, the toe-in (nose cones closer together) will increase under load. And, if the propellers are rotating inward (port clockwise and starboard counter-clockwise), the force will tend to pull the prop shafts closer together resulting in toeing the drives outward. The deviation is related to the type and condition of the gimbals and transom assemblies, and how high the propeller shafts are when the boat is underway. The result of the movement under load should be considered when deciding what the ultimate setup is relative to drive toe-in or toe-out.
Catamaran hulls that are running a high X dimension with the drive placement very close to the tunnel present additional criteria to consider. If the drives are close enough to the tunnel wall so that the sweep of the propeller blade is seeing clean water exiting from inside the tunnel, there is a tendency to neutralize the affect on the propeller created by water exiting from the angle of the running surface of the sponson.
The bottom line is to get some advice from the manufacturer or someone who knows a lot about your particular type of boat and setup. Then start from a setting and make minor adjustments testing the boat each time to gauge the affect on the handling and efficiency.
Always measure the toe-in or toe-out with the drives trimmed to a neutral position and the steering straight. With an assistant, measure from the front of the center of the nose cones or bullets compared to the center of the aft end of the prop shafts. If you run the boat and discover that the toe-in measurement has changed by itself, the indication is that there is significant slop in your transom assemblies, tiebar or steering. A change in the measurement also could be because the transom assemblies themselves are moving on the boat’s transom and need to be re-torqued.
TOE-IN OR OUT?
QUESTION: Can you explain the correct procedure for setting the drive alignment on a twin-engine boat? I would think that if they are not in correct alignment, you could be scrubbing speed.
On a car, there is a certain amount of toe-in, and when the car starts moving, that position will change. Is a boat the same? Does the procedure change with regard to the direction the props are turning?
ANSWER: Traditionally, the front suspension on an automobile is set up so the wheels have a slight amount of toe-in. Being that there is (probably more in the old days) a certain amount of slop or play in the suspension or steering components such as ball joints, drag links, bushings and so on, if the front wheels were not set slightly toed-in to keep a constant load in one direction, the result would be what is called a shimmy. A shimmy can lead to a violent shaking of the front wheels and the steering wheel.
The amount the drives should be toed-in or toed-out on a boat depends on a number of factors. The most common considerations are hull type, drive type, propeller shaft depth and propeller rotation.
Generally speaking, twin-engine V-bottom boats with the propellers spinning out are usually set up with the drives toed-in slightly. It is common to set the nose of the drives about 1/8-inch closer together than the aft end of the prop shafts. The theory is that water exiting from the back of the hull is being parted slightly by the keel, so setting the drives at a slightly toed-in angle would result in them running more aligned with the water flow. That is only a theory. What we do know is that certain boats handle better with varying degrees of drive toe-in or toe-out.
If the propeller shafts are high enough so the propellers are surfacing, the side load created by the propeller blades seeing cleaner water in the lower sweep of their rotation will tend to push the drive in one direction. Similar to an automobile suspension, there is a slight amount of play in the gimbal ring and transom assembly pins and attachments.
The side force created by a surfacing propeller will load the drive and transom assembly in the opposite direction of the propeller rotation. In other words, if the propeller is a right-hand rotation (clockwise from the rear), the result is that the force is the same as turning (or flexing) the drive to the right, and vice versa.
If your propellers are surfacing and turning out, the toe-in (nose cones closer together) will increase under load. And, if the propellers are rotating inward (port clockwise and starboard counter-clockwise), the force will tend to pull the prop shafts closer together resulting in toeing the drives outward. The deviation is related to the type and condition of the gimbals and transom assemblies, and how high the propeller shafts are when the boat is underway. The result of the movement under load should be considered when deciding what the ultimate setup is relative to drive toe-in or toe-out.
Catamaran hulls that are running a high X dimension with the drive placement very close to the tunnel present additional criteria to consider. If the drives are close enough to the tunnel wall so that the sweep of the propeller blade is seeing clean water exiting from inside the tunnel, there is a tendency to neutralize the affect on the propeller created by water exiting from the angle of the running surface of the sponson.
The bottom line is to get some advice from the manufacturer or someone who knows a lot about your particular type of boat and setup. Then start from a setting and make minor adjustments testing the boat each time to gauge the affect on the handling and efficiency.
Always measure the toe-in or toe-out with the drives trimmed to a neutral position and the steering straight. With an assistant, measure from the front of the center of the nose cones or bullets compared to the center of the aft end of the prop shafts. If you run the boat and discover that the toe-in measurement has changed by itself, the indication is that there is significant slop in your transom assemblies, tiebar or steering. A change in the measurement also could be because the transom assemblies themselves are moving on the boat’s transom and need to be re-torqued.
Coolerman
Charter Member
Hey John, just checked with Dennis and we set them at 1/8" as well (toed out because we spin in).
endeavor1
New member
Who is this Dennis guy and what would he know...... lol.... jking
endeavor1
New member
I believe he is the "Master" to our young "Grasshopper" friend....
Call me a Grasshopper then too.......... Dennis has helped me immensly over the years with questions i have had. Always a wealth of knowledge. Now Saxman on the other hand.... well, lets just say he is gonna be a great rail-roader!!!
spiker
New member
Ok next step - installing the engine hatch actuator due to engine configuration and piping in need to add an additional lift and use two, one on each side, i do not want to use the slides and would rather install the pivot connector directly to the hatch lid. looking for measurements on where you guys have your installed. Mine will be a little different as the hatch lid is 7" longer than any that were made due to making the engine room 7" longer to accomodate the staggered motors.
I cannot use the center stringer at all and will ned to mount on the outside stringers.
I cannot use the center stringer at all and will ned to mount on the outside stringers.
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