Prop paddlewheel problem

[GilesC]

I'm having nightmares about reversing in tight places (like a marina) because the paddle-wheel/prop walk is so dramatic on my boat. I end up almost hitting the nearest object to starboard - which is usually an expensive new boat with its owner watching - before I get any useful steerage.

I have a 15hp diesel on a fin keel Gibsea with a traditional shaft, twin blade, fixed prop and need some advice! Would a different prop make life any better, for example? Are folding props better or worse? Or (reluctantly) is a bow thruster the only thing likely to make a difference?

 

[Chris_Stannard]

I take it from what you say that your stern walks to port with a vengance. Before going into other solutions try the following. Rig a slip rope to the stern which can be held in hand whilst you are going astern, preferably by a crew member. Let you bow swing out a bit and give the engine a short burst of astern at high revs. This should get you moving and then you will be able to steer whilst the engine is idling. If you can practice this manouvre without your neighbour there several times

Chris Stannard

 

[Jacket]

Folding props are definitely worse!

I've got one on my boat, and really struggle when trying to go astern. The problem is that many folding props don't fully un-fold when put in astern, so you get all the prop walk, without much drive astern.

I don't know how long you've had your boat, but if its only a year or so, don't give up and get a bow thruster (horrid things!). I got very fed up with my boat for a while, but if you keep persevering (And while doing so, have someone handy with a spare fender!) eventually you can handle the prop thrust and manover succesfully in most circumstances.

Have you tried the following:

i) Give the engine a short, sharp burst in astern. You'll get some prop walk, but as its only for a second or two it doesn't matter.

ii) Stick the engine in neutral. As there's now no prop walk, you'll find you can steer. Straighten the boat up.

iii) Once you've got the boat pointing in the right direction again, put the engine gently in astern. Now you've got some steerage way, you'll find you're able to steer to overcome the propwalk.

Works for me in anything other than a strong side wind.

 

[burgundyben]

Giles,

For 5 years I worked for a yacht charter firm where the boats were tighly packed so parking a yacht is something I can do. You dont mention the size and displacement of your boat, but a fixed prop is much much better than a folding one for the purposes of parking, but crap for sailing performance, anyhow, I guess if your boat has 15hp its about 28 foot or a little more? Anyhow, remember when you swing the tiller to starboard to counter act the prop walking the back of the boat that way that if you are coming out of a space that there is no water flow over the rudder so it wont do bugger all, but getting out should not be too bad, keep the rudder central till you can feel some water flowing over it, other wise its just acting as a brake.

When you want to go from going forwards to going backwards, move the tiller to port so that the stern goes to port about say 30 degrees whilst still moving forwards and clonk her into reverse with just a few revs on, that way it will take a few yards to stop and give you the chance to correct the tendancy to swing to starboard whilst you still have some way on, gett it? if not PM me. Plus, got out for a day, this time of year great as lots of empty pontoons and practice parking all day, it will make loads of difference.



"Who was he?"

 

[burgundyben]

Giles,

For 5 years I worked for a yacht charter firm where the boats were tighly packed so parking a yacht is something I can do. You dont mention the size and displacement of your boat, but a fixed prop is much much better than a folding one for the purposes of parking, but crap for sailing performance, anyhow, I guess if your boat has 15hp its about 28 foot or a little more? Anyhow, remember when you swing the tiller to starboard to counter act the prop walking the back of the boat that way that if you are coming out of a space that there is no water flow over the rudder so it wont do bugger all, but getting out should not be too bad, keep the rudder central till you can feel some water flowing over it, other wise its just acting as a brake.

When you want to go from going forwards to going backwards, move the tiller to port so that the stern goes to port about say 30 degrees whilst still moving forwards and clonk her into reverse with just a few revs on, that way it will take a few yards to stop and give you the chance to correct the tendancy to swing to starboard whilst you still have some way on, gett it? if not PM me. Plus, got out for a day, this time of year great as lots of empty pontoons and practice parking all day, it will make loads of difference.



"Who was he?"

 

[bedouin]

To extent you will have to learn to live with propwash - once you learn how to manage it you will make allowances.

A more efficient propellor will help in that you will get steerage way faster; so a 3-blade fixed will be better than a 2, and a folding prop will usually be worse than a fixed.

The other alternative is one of the feathering props (e.g the MaxProp) or the Autoprop. These will both be more efficient in reverse than any fixed, and because of the way they work the will change the prop wash - probably reducing it significantly. The trouble is that they are expensive, especially if they don't fix the problem!

 

[philip_stevens]

I fully agree with Bedouin about a three blade prop in place of the two blade prop. I had a 2 blade prop on my Konsort, and it was just about impossible to get any slow speed steerage going astern. I then fitted a 3 blade prop, and the difference was amazing. There is now no problem in going astern, even at slow speed.

regards,
Philip

 

[Avocet]

Will your boat even go astern in a straight line without the prop turning at all? i.e. if you can get it moving and then slip into neutral are things OK? If not, (as on my boat) I think you'll just have to live with it and develop warping techniques - that's waht I've ended up doing!

 

[Miker]

I've got a two blade Autoprop which is a doddle in reverse provided that you remember to give it a quick burst before adjusting the revs to suit. It also stops on a sixpence.

 

[bedouin]

Yes - I wanted one of those, but it won't fit on my boat :-(

 

[bedouin]

I was at LIBS yesterday, and one of the things I was looking at was a replacement propellor, aiming among other things to improve handling in reverse.

With that in mind the Gori 3-blade folding looks ideal - it is unique among folders in that it always presents the same leading edge whether in forward or reverse, being a three bladed prop it's reverse performance will be as good as any prop on the market. The downside is that it is very expensive.

 

[Spacewaist]

Prop walk is your friend!

"Prop walk" is your friend, not something to banish. It adds manouvrability. With your starboard walk, coming along side in a small space to starboard, a sharp burst astern will bring the stern in at the same time as stopping the boat. It also makes a U-turn much easier (to port - and much more difficult to starboard!).

There are drawbacks (eg leaving that starboard along side berth!!) but a bit of planning and the judicious use of warps will solve any problem.

Make friends with it, and learn its idiosyncracies - you'll be very happy together.

There are plenty of posts here on how to get to grips with it - so I wont repeat here. I will say, though, that I have a feathering "J" Prop on my HR 42 with probably the most vicious prop walk I have seen in any boat. We are (now) good friends, but it took time - not all featherin props are free of walk.

A pontification from the Panjandrum of orotund bloviation AD2002

 

[FlyingSpud]

It is rarely just a problem of propwalk, windage and tide also play a big problem, and you have to try to balance all 3. Unlike the other two, at least propwalk tends to be the same every time, and once you have come to terms with it, the its predictability is an aid as, in effect, it amounts to a ‘stern thruster'.

Work out a plan before you start to move – treat each case as a logic problem – and never be afraid to use warps, or at least set them up to use in case things go wrong.

If, no matter how many times you try you have a problem, see if someone else (your neighbour maybe) would come on your boat and give some guidance, better still, if you can afford it, hire one of the local gurus for a morning just in the Marina going in and out of berths at different angles to the wind so that you can ‘feel’ and see what the good advice given by others means in practice.

 

[alan]

Whilst ackowledging the good advice of the other replies, I can also say that adding a 'feathering' prop will make a difference. I have experienc

Alan Cloke

 

[alan]

Whilst ackowledging the good advice of the other replies, I can also say that adding a 'feathering' prop will make a difference. I have experience of your problem on a firiends light displacement cruiser originally fitted with a fixed two blade prop; he changed the prop for a Maxprop and the difference in astern was dramatic - virtually no more propwalk and immediate thrust.

Good luck,
Alan.
Nettuno, Italy.

Alan Cloke

 

[Chris_Robb]

Re: Prop walk is your friend!

Yes - I agree that prop walk is highly useful. I have a long keeled Victory 40 which has little if any propwalk, which I find makes manouvering in tight places very much more difficult.

 

[GilesC]

Thanks to everyone who replied - all useful stuff!
I've known this boat, in this marina now for almost 12 years, and its always been difficult - and yes, when its calm (locked basin, so never any tide) I can just about do it, but as soon as the wind gets up its hopeless. Interestingly, virtually no-one else in the marina moors stern-to so I don't think its just me - they all vault over their pulpit which I think is more dangerous.
Anyway, following some of the advice here, and after a day at the boat show, I will shortly become the proud owner of a feathering 3 blade prop, so here's hoping it makes the difference!

Thanks again

 

[Miker]

Out of curiosity, which one? NM

NM

 

[GilesC]

Re: Out of curiosity, which one? NM

I'll check, but I think it was called a JF prop - from the same people who sell Maxprop (which I couldn't afford). I can get you the details if you're interested.

 

[Miker]

Re: Out of curiosity, which one? NM

No thanks. I've got an Autoprop fitted. As I said, I was just curious.