What's wrong with a bit of prop walk?

[john_morris_uk]

I have noticed in several threads and in various places that people measure how good a propellor and boat configuration is by how small an amount of prop-walk that occurs when the boat goes into astern. I wonder whether this makes complete sense - or at least whether its the whole story? Whilst I might agree that a huge amount or excessive prop-walk is a pain in the back side (if you'll pardon the pun?) I don't have any problem with a controlled and predictable moderate amount of prop walk on a boat. If anything I think it makes the boat easier to handle in tight spaces.

You can use prop-walk to help you turn or to put you neatly alongside a pontoon in a confined space (so long as you can choose which way round to face) and you can use it to turn the boat round in not much more that its own length. Of course having prop-walk means a boat will have a 'preferred side to' when coming alongside, but I have never found this a problem. So long as the prop-walk isn't too extreme, there are tricks to use when coming alongside the 'wrong way round'.

All in all, I wonder where this movement for minimum or no prop-walk comes from? For me, prop-walk is a friend and ally in boat handling. Any ideas why almost any amount of prop-walk seems to be despised by some?

 

[Victoria Sponge]

The trick is to really know about your prop walk and then use it to your advantage.

 

[Poignard]

It helps me when picking up a mooring. I bring the boat slowly to a point where the buoy is a couple of feet off the starboard bow and then engage astern gear. The prop walk moves the bow to starboard so the buoy comes close and the Old Guvnor can drop a lassoo over it easily. If, as sometimes happens, she manages to mess it up the boat is starting to move astern away from the buoy anyway, so I can then go forward again for another go (whilst screaming abuse at her).

 

[stav]

Afraid I can not offer an opionion as to why prop walk is considered so evil; I am with you and agree it can be useful. Just the yachting press taking a line and the desiree for not having to think it through before hand? And marinas wanting to squeeze people in to tighter spots but then I keep a length of 8mm for gently springing out against the prop walk.

 

[Victoria Sponge]

It helps me when picking up a mooring. I bring the boat slowly to a point where the buoy is a couple of feet off the starboard bow and then engage astern gear. The prop walk moves the bow to starboard so the buoy comes close and the Old Guvnor can drop a lassoo over it easily. If, as sometimes happens, she manages to mess it up the boat is starting to move astern away from the buoy anyway, so I can then go forward again for another go (whilst screaming abuse at her).

I always do the helming when we pick a mooring up. That's the easy bit! The hard part is done by HWMBO who has long arms and is much stronger. You should try it. No abuse on our boat.

 

[sailorman]

I have noticed in several threads and in various places that people measure how good a propellor and boat configuration is by how small an amount of prop-walk that occurs when the boat goes into astern. I wonder whether this makes complete sense - or at least whether its the whole story? Whilst I might agree that a huge amount or excessive prop-walk is a pain in the back side (if you'll pardon the pun?) I don't have any problem with a controlled and predictable moderate amount of prop walk on a boat. If anything I think it makes the boat easier to handle in tight spaces.

You can use prop-walk to help you turn or to put you neatly alongside a pontoon in a confined space (so long as you can choose which way round to face) and you can use it to turn the boat round in not much more that its own length. Of course having prop-walk means a boat will have a 'preferred side to' when coming alongside, but I have never found this a problem. So long as the prop-walk isn't too extreme, there are tricks to use when coming alongside the 'wrong way round'.

All in all, I wonder where this movement for minimum or no prop-walk comes from? For me, prop-walk is a friend and ally in boat handling. Any ideas why almost any amount of prop-walk seems to be despised by some?

We have a kick like a mule & love it, she can almost turn in her own length

 

[Richard10002]

The trick is to really know about your prop walk and then use it to your advantage.

+1

and not to fight it - a bit like the wind.

 

[l'escargot]

I once replaced the gear box in a boat with one with a different ratio and went from a 3 bladed prop to a 2 blade and virtually eliminated the prop walk - I hated it and it made the boat harder to park. My current boat has a big 3 bladed prop and it is almost as good as a thruster in some situations. I don't think I would like a boat with no prop walk at all.

 

[Deleted member 36384]

..... All in all, I wonder where this movement for minimum or no prop-walk comes from? For me, prop-walk is a friend and ally in boat handling. Any ideas why almost any amount of prop-walk seems to be despised by some?

Perhaps it started when bow thrusters reached a certain mass in the market place along with the rise of modern, low cost, hulls which conceded with instant communication and certainty. The modern sailor wants a certain amount of predictability compared to the uncertainty sailors used to live with: GPS, Mobile Phones and EPIRB are examples of common certainty of function, as is the Bowthruster. Can you imagine the horror that the modern sailor faces when the boat is brought to a halt under power and she turns!

Its a general trend in the world, no one wants uncertainty, everyone is deluded. Thats my theory anyway.

 

[Tranona]

Having two boats, one with strong prop walk and one with very little, I think I prefer the latter on balance, particularly in its original environment in the Med when straight line backing up to the quay was everyday. The old wooden long keeler only goes one way, and I remember my examiner being impressed at my ability to get it out of the berth backwards and turn it in its own length, but I did suggest he not ask me to do it the other way round! Unfortunately you don't always have the choice.

 

[Blueboatman]

''Prop walk is your friend''. especially in natty 3 point turns

 

[Elemental]

The trick is to really know about your prop walk and then use it to your advantage.

Assuming it can be used to advantage...

Better, I feel to have a boat that follows the rudder in reverse as it would going forwards. Just as predictable but perhaps requiring a more precise level of control as you lose the option to get the boat into approximately the right posn and then use propwalk to crab into position

Would you like a car that didn't steer properly...?

 

[john_morris_uk]

Having two boats, one with strong prop walk and one with very little, I think I prefer the latter on balance, particularly in its original environment in the Med when straight line backing up to the quay was everyday. The old wooden long keeler only goes one way, and I remember my examiner being impressed at my ability to get it out of the berth backwards and turn it in its own length, but I did suggest he not ask me to do it the other way round! Unfortunately you don't always have the choice.

Well as another examiner, I sincerely hope that your examiner on the day was well aware that you could only do it the one way round!

 

[john_morris_uk]

Assuming it can be used to advantage...

Better, I feel to have a boat that follows the rudder in reverse as it would going forwards. Just as predictable but perhaps requiring a more precise level of control as you lose the option to get the boat into approximately the right posn and then use propwalk to crab into position

Would you like a car that didn't steer properly...?

Hmm - that's why I said 'moderate amount of prop. IMHO the car analogy is a red herring - and actually turns out to be a harmful analogy. If people want boats that steer like cars, then they will be wanting to do away with wind and tide and leeway next.

A boat isn't a car - and it doesn't steer like one even if its got no prop walk at all. The pivot point in a keel boat is usually somewhere just behind the mast when you are going forwards and when you go backwards, the pivot point appears to move aft a little. The result is something that steers VERY differently to a car.

And that's before we start on the steering of large twin engined power boats at very slow speed where the steering wheel is redundant by and large and should usually be left well alone.

 

[Searush]

There's the answer then, it's people who think boating is like driving a car.


It makes sense to me. I learned to use currents & edddies in a white water kayak, so ferry glides & break outs were a doddle, but prop walk had me foxed until I understood what was happening. Now it's my friend.

The big difference came when I switched from L/H toR/H prop & started berthing alongside in a slow & steady current rather than the raging wash of eddies at Conway (where prop wash was generally swamped by tide).

 

[Poignard]

I always do the helming when we pick a mooring up. That's the easy bit! The hard part is done by HWMBO who has long arms and is much stronger. You should try it. No abuse on our boat.

No no, that won't do at all. I do all the hard work - scraping, painting, anchoring, engine repairs etc. so it's only fair that I get to play Captain.

Anyway, I position the boat so perfectly that picking up a mooring is easy for her. (Liar - Ed.)

 

[sailorman]

Assuming it can be used to advantage...

Better, I feel to have a boat that follows the rudder in reverse as it would going forwards. Just as predictable but perhaps requiring a more precise level of control as you lose the option to get the boat into approximately the right posn and then use propwalk to crab into position

Would you like a car that didn't steer properly...?

helm hard-a-Stbd she does go straight astern from stationary, once she moves helm mid-ships & she follows the rudder.
coming along side a quick burst astern & she lays along the berth to port

 

[Elemental]

helm hard-a-Stbd she does go straight astern from stationary, once she moves helm mid-ships & she follows the rudder.
coming along side a quick burst astern & she lays along the berth to port

Sure, now berth it stbd side to with a wind blowing from stbd.

Of course propwalk can be useful, my point is that it can also work against you and it isn't always possible to re-structure your manoeuvre to take advantage of it. My boat need more than a trace of sternway before she follows the rudder too.

I'd just prefer less propwalk, not necessarily nil.

 

[Elemental]

Hmm - that's why I said 'moderate amount of prop. IMHO the car analogy is a red herring - and actually turns out to be a harmful analogy. If people want boats that steer like cars, then they will be wanting to do away with wind and tide and leeway next.

You're right - the car analogy was poor (it was late when I replied).

I tend to agree with you that a moderate amount of leeway is no bad thing. However, some boats (and I count my own here) have large propwalk effects so I'm interested in reading about how different props behave in reverse in an attempt to mitigate the effect.

 

[Easticks28]

''Prop walk is your friend''. especially in natty 3 point turns

+1