whenever she's under power only. As I increase the throtle the more she turns. I didn't notice anything last season, since I kept the pedestal brake somewhat tight. However this year I installed an Autohelm and the wheel and rudder turn to port whenever we are under power. Can anyone help rationalize this very annoying distraction? Thx so much -Chuck '83 Cat 30
- Status
Prop Walk
Chuck They ALL do that. It's because of the turning of the propellor. Check the archives on "prop walk" and you'll get an education. Stu
Chuck They ALL do that. It's because of the turning of the propellor. Check the archives on "prop walk" and you'll get an education. Stu
Prop walk--in forward at 5 knts?
That seems a bit odd -- especially with a 3-blade prop in forward gear at 3,4 or 5 kts. to port not starboard... -Chuck
That seems a bit odd -- especially with a 3-blade prop in forward gear at 3,4 or 5 kts. to port not starboard... -Chuck
Can't be prop-walk, the wheel also turns...
Not only does it steer itself to port, it stays that way - so I'm not sure it is the rudder either -- I really need input on this one... Perplexed, -Chuck
Not only does it steer itself to port, it stays that way - so I'm not sure it is the rudder either -- I really need input on this one... Perplexed, -Chuck
Auto Pilot
If I understand right you are having this problem when your autopilot is on? It's gotta be the autopilot. It should correct for any prop walk or anything else that would cause the boat not to go straight. Are you sure it is even working?
If I understand right you are having this problem when your autopilot is on? It's gotta be the autopilot. It should correct for any prop walk or anything else that would cause the boat not to go straight. Are you sure it is even working?
It happens only when the autopilot is off
...and it's under power. It makes absolutely no sense. I'd hate to pay $200 to haul it out for a common problem... Thx, -Chuck
...and it's under power. It makes absolutely no sense. I'd hate to pay $200 to haul it out for a common problem... Thx, -Chuck
Prop Walk
I also own a Catalina 30 with an M-25XP and a fixed 3 blade prop. In reverse, the stern goes to port. In Forward, the stern goes to starboard, causing her to steer to port. This increases with speed when motoring. This is a classic C30 occurance and they all do it to some extent. Everybody I know just lives with it 'cause she's a SAILboat. Check out the International Catalina 30 Association at the link below.
I also own a Catalina 30 with an M-25XP and a fixed 3 blade prop. In reverse, the stern goes to port. In Forward, the stern goes to starboard, causing her to steer to port. This increases with speed when motoring. This is a classic C30 occurance and they all do it to some extent. Everybody I know just lives with it 'cause she's a SAILboat. Check out the International Catalina 30 Association at the link below.
Mike -- please confirm...
…that irrespective of the autopilot; when you are motoring along with the pedestal brake loosened, your steering wheel turns itself to port and it remains there. Your explanation does make sense, as now does Stu Jackson’s. Please confirm and satisfy this anal sailor… Thx so much, -Chuck
…that irrespective of the autopilot; when you are motoring along with the pedestal brake loosened, your steering wheel turns itself to port and it remains there. Your explanation does make sense, as now does Stu Jackson’s. Please confirm and satisfy this anal sailor… Thx so much, -Chuck
Yes. prop walk.
Yes, the action of prop walk will turn the boat to starboard and the wheel (I have a tiller) reacts accordingly. One of my favorite places is about 20 miles away and many times there is no wind in the morning so I motor the 20 miles. It can be quite a task to hold the tiller to steer a straight course at cruising speed (5.5 to 6.0 knots), so I use my autopilot. A three blade prop causes more walk than a 2 blade, or the more effecient the prop the more the walk. On the IC30A site is a link to a mailing list with over 300 listees and this topic comes up occasionally. Check these archives for a more in depth answer on the physics of prop walk.
Yes, the action of prop walk will turn the boat to starboard and the wheel (I have a tiller) reacts accordingly. One of my favorite places is about 20 miles away and many times there is no wind in the morning so I motor the 20 miles. It can be quite a task to hold the tiller to steer a straight course at cruising speed (5.5 to 6.0 knots), so I use my autopilot. A three blade prop causes more walk than a 2 blade, or the more effecient the prop the more the walk. On the IC30A site is a link to a mailing list with over 300 listees and this topic comes up occasionally. Check these archives for a more in depth answer on the physics of prop walk.
Check
Pretty easy to check if it's prop walk. With A/P off, motor along at 5 knots, throttle back, shift to neutral, take your hands off the wheel, and see if the boat continues along on a straight course with no pull to port. My C30 has prop walk, bow to port, in fwd gear as well, w/ 3-blade MaxProp.
Pretty easy to check if it's prop walk. With A/P off, motor along at 5 knots, throttle back, shift to neutral, take your hands off the wheel, and see if the boat continues along on a straight course with no pull to port. My C30 has prop walk, bow to port, in fwd gear as well, w/ 3-blade MaxProp.
- Status