I have had conflicting reports concerning a hard pull to port when the boat is under power, which is my condition. The prop that came with the boat is a 18x12 3 blade fixed prop. The wind or waves do not affect the condition. If you release the wheel when the engine is at least 2500RPM or more the boat will make a hard emergency turn to port and the wheel will spin like a top. I was wondering if anyone else has had this experience and what if anything was done to solve it or lessen the pull. The boat also reacts very slowly to a reverse input. It takes quite a while when going at 1 knt or less for the boat to respond to reverse. I have also heard that this is not a problem in other models. Any input would be appreciated.
Prop Walk
- Thread starter Cookie4167
- Start date
- Status
- Not open for further replies.
J
John Richard
My experience is
Cookie, I have a 410 with a two blade prop. While under power cruising at 3000 rpm, per Yanmar recommendations, the boat will pull violently when you remove your hands from the wheel. I think this is a natural tendency based upon the engine's rotation and its rpm's. When backing, you need to initially accelerate to get a flow of water going past the rudder. When you first go into reverse, it takes a good amount of throttle to get the boat moving. You will notice a pronounced movement to port until you get steerage. Once accomplished, pull back the throttle and you can steer very easily. The secret to backing is to do so in neutral to eliminate any excessive movement to port. John Richard s/v Jack's Place
Cookie, I have a 410 with a two blade prop. While under power cruising at 3000 rpm, per Yanmar recommendations, the boat will pull violently when you remove your hands from the wheel. I think this is a natural tendency based upon the engine's rotation and its rpm's. When backing, you need to initially accelerate to get a flow of water going past the rudder. When you first go into reverse, it takes a good amount of throttle to get the boat moving. You will notice a pronounced movement to port until you get steerage. Once accomplished, pull back the throttle and you can steer very easily. The secret to backing is to do so in neutral to eliminate any excessive movement to port. John Richard s/v Jack's Place
J
Jim
I'm no expert but,
seems to me you're just experiencing the normal torque (in opposite direction) produced by the clockwise spin of the propeller, and not unexpected. And, once you get that big rudder just a little off center it's more or less a done deal at that point as, un-restrained, it's going to go hard over just as you've experienced. Just ask any sailor motoring w/ AP engaged when the AP power is interupted. (Stink boats use trim tabs to counteract the effect/force and balance the wheel). As for as reverse, your description seems about right: small (relatively) prop and a lot of displacement/momentum to overcome so would not be immediate/quick response even at slow speeds. And, you'll probably back to port better than starboard. Good article in Chapmans' re prop walk, and "emergency" turns in tight quarters. The above based on my prior experience with power/sail and my current 8 ton Vision 36 with a 38 HP diesel.
seems to me you're just experiencing the normal torque (in opposite direction) produced by the clockwise spin of the propeller, and not unexpected. And, once you get that big rudder just a little off center it's more or less a done deal at that point as, un-restrained, it's going to go hard over just as you've experienced. Just ask any sailor motoring w/ AP engaged when the AP power is interupted. (Stink boats use trim tabs to counteract the effect/force and balance the wheel). As for as reverse, your description seems about right: small (relatively) prop and a lot of displacement/momentum to overcome so would not be immediate/quick response even at slow speeds. And, you'll probably back to port better than starboard. Good article in Chapmans' re prop walk, and "emergency" turns in tight quarters. The above based on my prior experience with power/sail and my current 8 ton Vision 36 with a 38 HP diesel.
B
Bradley Cavedo
No pull on our P42
Cruising at 3100 rpm with our two blade flex o fold prop, 17 x 15, I can take my hands off the wheel and it will steer straight ahead; no pull either way.
Cruising at 3100 rpm with our two blade flex o fold prop, 17 x 15, I can take my hands off the wheel and it will steer straight ahead; no pull either way.
prop-walk
My 37C also had a horrific drive to port under forward power. I found that ht prop was over-pitched such that the engine could not reach its full rpm, and thus its torque was limitted! The almost perfect cure was to increase the prop diam. to 15 inches and reduce the pitch by 1..Now I can drive the boat at 2900 rpm and 7.5 knots. The wheel pull to port, while not eliminated, has been greatly reduced!
My 37C also had a horrific drive to port under forward power. I found that ht prop was over-pitched such that the engine could not reach its full rpm, and thus its torque was limitted! The almost perfect cure was to increase the prop diam. to 15 inches and reduce the pitch by 1..Now I can drive the boat at 2900 rpm and 7.5 knots. The wheel pull to port, while not eliminated, has been greatly reduced!
My Boat Walks Too!
I've had my 44 for a year now and have gotten used to it. Just before the boat stops it's motion I put in a little steering to port to counteract the port prop walk in reverse. I've also learned to get the high RPM reversing reduced as soon as possible after momentum has been gained in reverse motion to reduce the thrust that causes the walk. After the boat is moving the walk is not as much of a factor. I've even started to use it in my favor when backing into my tight slip. I had a 340 that did the same thing. I think it's a characteristic of large Hunter boats. By the way, what do you think about the cushion for your salon table when you convert in into a berth? Do you have the 1" high hill in the center of the boat like we do?
I've had my 44 for a year now and have gotten used to it. Just before the boat stops it's motion I put in a little steering to port to counteract the port prop walk in reverse. I've also learned to get the high RPM reversing reduced as soon as possible after momentum has been gained in reverse motion to reduce the thrust that causes the walk. After the boat is moving the walk is not as much of a factor. I've even started to use it in my favor when backing into my tight slip. I had a 340 that did the same thing. I think it's a characteristic of large Hunter boats. By the way, what do you think about the cushion for your salon table when you convert in into a berth? Do you have the 1" high hill in the center of the boat like we do?
Thanks
Appreciate all the input. It appears that the prop walk is the nature of the beast and from what I have read would be attributed to the size on the prop and the angle of the drive shaft. It also appears that Hunter produces more prop walk than other makes of boats. It appears that I will have to live with it. In response to the center cushion, I have not tried mine, but it appaears that the cushion will sit higher than the others when the table is lowered. Will make for an interesting sleeping position.
Appreciate all the input. It appears that the prop walk is the nature of the beast and from what I have read would be attributed to the size on the prop and the angle of the drive shaft. It also appears that Hunter produces more prop walk than other makes of boats. It appears that I will have to live with it. In response to the center cushion, I have not tried mine, but it appaears that the cushion will sit higher than the others when the table is lowered. Will make for an interesting sleeping position.
- Status
- Not open for further replies.