Getting out of a finger berth astern (basic prop walk question)

[Yealm]

My old boat’s also a nightmare in reverse at low speeds in marinas- my only advice is to insist on a port side berth!

 

[Birdseye]

My question is does rigging the bow bridle and driving astern against it before slipping it stop prop walk (as the prop is moving water about.....)

No. In astern your prop kicks water out to one side of the boat - its a function of that sort of prop design. Then Newtons third law applies and pushing water out to one side pushes the boat stern in the opposite direction. Same principle that applies to an oar or a jet plane or a cricket bat hitting a ball.

As water flow builds up over the rudder so you gain enough control to exert an opposing force and steer the boat straight. But the prop walk doesnt go away and you are still steering to counteract it, so once you get enough speed up, it can be good to stop the prop turning and steer with the rudder alone. Particularly the case with a heavy old long keeler with small rudder area

 

[Stemar]

With her old prop, Jissel was completely predictably going astern. Kick to port, then weathercock to face downwind. Until the time I relied on her doing just that, which would have made for an elegant departure demonstrating consummate skill, when she did the exact opposite.

And this, Ladies and Gentlemen is why a boats is always a she.

 

[dom]

With her old prop, Jissel was completely predictably going astern. Kick to port, then weathercock to face downwind. Until the time I relied on her doing just that, which would have made for an elegant departure demonstrating consummate skill, when she did the exact opposite.

And this, Ladies and Gentlemen is why a boats is always a she....

And 'happy reversing' to you Dear Sir, for bang goes your job prospects at the BBC!

The mere use of terms like 'he' and 'she' - not just in contrived connotations for stereotypical representation - can cause deep offence to some.

 

[johnalison]

And 'happy reversing' to you Dear Sir, for bang goes your job prospects at the BBC!

The mere use of terms like 'he' and 'she' - not just in contrived connotations for stereotypical representation - can cause deep offence to some.

Precisely, which is why we use them.

 

[Stemar]

I never realised such a thing could cause offence. I must strive to be more consistently offensive in such ways.

 

[graham]

Prop walk only occurs while the prop is turning.Use a big thrust of power to get the boat moving then into neutral now the rudder will be in control.It takes two short blasts of power to get my boat clear of the finger pontoon .

 

[SimonFa]

This weekend was the first time I have gone out of a finger berth astern. Since my prop walk kicks to port I was concerned I would be rubbing fenders with my neighbour (moored starboard side to). My concern was due to a lack of practice as we dodge marinas on the whole. I use Duncan Wells Stress Free Sailing book which recommended a bow bridle to keep the boat parallel to the pontoon but I was concerned that as soon as I started moving the prop walk would kick in and I'd be off to port before gaining steerage. My question is does rigging the bow bridle and driving astern against it before slipping it stop prop walk (as the prop is moving water about.....)
If people don't know what a bow bridle is there's a video by DW here

I'm happy springing off from alongside berths but realised I haven't done finger berths.
Cheers for any pointers
PS Tide and wind were negligible and nothing bad happened, but I wish I had understood my prop walk and bridle theory better, just for peace of mind beforehand

My first thought is that only one boat should have fenders out otherwise you risk a tangle and a stanchion or 3. When I was in Weymouth and there wasn’t much room I agreed with the skipper next to me that it would always be me. This is also the same when rafting.

As to prop walk, as mentioned above a 2 second blast should give you enough way to get straight ou, but you didn’t mention wind which can be a bigger factor.

As I & someone else mentioned in another thread, get a bow fender or rig up up one of your normal fenders*, leave bow and eased stern lines on, put the boat in tick over ahead and ease the springs so she creeps forward on to the cat walk, steer full away so the stern is being pushed in to the finger and you can take time getting the rest of your lines in. In strong winds blowing you off you might need more than tick over.

You can depart when ready, I centre the wheel first then give a blast astern.

*I did this in Cherbourg and got some puzzled looks.

I‘m sure you could do something similar with a tiller.

 

[bitbaltic]

our boat is quite light for a 30 footer and has next to no prop walk so (unless there is strong wind or tide) I usually jump onto the finger and loose the lines before the crew (wife standing somewhere near the helm) has had time to realise they are taking the boat off and panic appropriately. I then tell them to hold the stick straight and give it a burst of welly while I just walk the boat off and then come the helm to make whatever manoeuvre comes next.
Pretty much works every time and prevents crew panic around a perceived critical role.

 

[Shuggy]

Our boat has the prop nearer the centre point between bow and stern. The rudder is nine feet from the prop. The prop points down below the rudder. When you engage astern the prop does not ‘pull’ the boat astern but tends to result in the boat deciding what to do. We’ve had her for 11 seasons; I’ve never managed to work out how to deal with it. The only rough rule of thumb is that more than 50% of the time the wind will blow the bow downwind. But not always. Best thing is to let her do what she wants to do and try to sympathise. I’ve learned that the best approach is to be totally chilled and pretend everything is just fine. Panicking results in more bad behaviour from the boat.

 

[johnalison]

our boat is quite light for a 30 footer and has next to no prop walk so (unless there is strong wind or tide) I usually jump onto the finger and loose the lines before the crew (wife standing somewhere near the helm) has had time to realise they are taking the boat off and panic appropriately. I then tell them to hold the stick straight and give it a burst of welly while I just walk the boat off and then come the helm to make whatever manoeuvre comes next.
Pretty much works every time and prevents crew panic around a perceived critical role.

I'd like to be there with my camera when she overdoes it and leaves you on the pontoon.

My boat is about 5 tons, so your way is not so easy. The wind tends to be guiding factor in my decisions but my usual method, as I have said, is the quick-burst-then-neutral way, but generally I start with the rudder full across, which is less than 45 degrees, to counter the prop wash, and if this and the wind combine to have me going straight I can just idle the engine instead of going to neutral.

 

[bitbaltic]

I'd like to be there with my camera when she overdoes it and leaves you on the pontoon.

you’ve rumbled my plan to shortcut the sailing and go straight from the caff breakfast to the pub.

 

[Buck Turgidson]

I have a Twister. I park bows in. The only way I can successfully get out is to warp her stern to stbd then give a blast and then off the power and let her arc her way out. Even in neutral the momentum she has from the blast of power is more than the rudder can overcome. In fact the rudder is almost completely useless when reversing and only the smallest of angles result in anything close to control.

When coming in the technique is akin to a hand break turn where reverse is used to straighten into the berth and slow her down. if I have too much way on I will kiss my neighbour but he knows and we fender for it.

It's impossible to describe the vagaries to anyone who has only sailed a modern AWB which in my experience with them in chartering and training are an absolute doddle to manoeuvre in close quarters.

She does pirouette rather elegantly to stbd though with just a touch of forward then idle reverse for the spin.

 

[James_Calvert]

It all depends on the circumstances doesn't it.

On a very calm day it's nice to just walk the boat out of the berth pushing on the guardrails/stanchions/whatever, climb aboard then start the engine so waking the crew too late for any thought they might have had of delaying departure. I've never wholly managed this, the sound of ropes being dropped on deck generally got my wife up, if not our younger crew.

If it's a little more tricky I will do much the same but walking along with the forward breast rope to hold the bow in, whilst my wife puts the engine gently in reverse and holds the tiller central.

Once I'm aboard it depends again. Whatever is needed to stop our bow clouting the boat in the adjacent berth. Hopefully nothing particular will be needed, the stern will turn towards the wind, which will determine whether we reverse or go forward to exit. In extremis I might need to hand the bow along the adjacent boat until all is clear but this is rare, although we are prepared to do so.

The aim throughout as long as it it feasible being to use the minimum speed and power possible, so reducing if not avoiding altogether consequences of misjudgements or mishaps.

Other circs may require a more powered up technique, in which case if I think the bow needs keeping close to the finger we would keep a bow slip rope on until the last moment to achieve this, being prepared to drop it entirely if it jams.

The bow being blown or set onto the finger is more a fendering problem, until a bit of power draws us away. An initial lean forward against a bow spring rigged for slipping may ease the finger clearance, if there is enough space in the berth.

 

[[3889]]

It all depends on the circumstances doesn't it.

On a very calm day it's nice to just walk the boat out of the berth pushing on the guardrails/stanchions/whatever, climb aboard then start the engine so waking the crew too late for any thought they might have had of delaying departure. I've never wholly managed this, the sound of ropes being dropped on deck generally got my wife up, if not our younger crew.

If it's a little more tricky I will do much the same but walking along with the forward breast rope to hold the bow in, whilst my wife puts the engine gently in reverse and holds the tiller central.

Once I'm aboard it depends again. Whatever is needed to stop our bow clouting the boat in the adjacent berth. Hopefully nothing particular will be needed, the stern will turn towards the wind, which will determine whether we reverse or go forward to exit. In extremis I might need to hand the bow along the adjacent boat until all is clear but this is rare, although we are prepared to do so.

The aim throughout as long as it it feasible being to use the minimum speed and power possible, so reducing if not avoiding altogether consequences of misjudgements or mishaps.

Other circs may require a more powered up technique, in which case if I think the bow needs keeping close to the finger we would keep a bow slip rope on until the last moment to achieve this, being prepared to drop it entirely if it jams.

The bow being blown or set onto the finger is more a fendering problem, until a bit of power draws us away. An initial lean forward against a bow spring rigged for slipping may ease the finger clearance, if there is enough space in the berth.

A calm day is the time to polish and refine close quarter handling skills. Manhandling a boat at any time smacks of incompetence, more so if using guard wires and stanchions. It is a worthless technique with 20 tons of vessel or 30 knts of wind. Why not do it properly all the time, especially when properly equals easily?

 

[capnsensible]

A calm day is the time to polish and refine close quarter handling skills. Manhandling a boat at any time smacks of incompetence, more so if using guard wires and stanchions. It is a worthless technique with 20 tons of vessel or 30 knts of wind. Why not do it properly all the time, especially when properly equals easily?

Sorry, that doesn't make sense to me. Not every boat is twenty tons. A boat below thirty feet is easy to give a little shove as needed. Not doing so is like not bothering to use a bow thruster that's fitted.
Why don't people make better use of boat hooks? The handle end used to fend of a cleat or something strong works just fine and is the equivalent to a push. And have plenty of fenders.
Practicing on windy days really teaches how to Manouver boats. Calm days then become a doddle.
All in my opinion, of course.

 

[TernVI]

A calm day is the time to polish and refine close quarter handling skills. Manhandling a boat at any time smacks of incompetence, more so if using guard wires and stanchions. It is a worthless technique with 20 tons of vessel or 30 knts of wind. Why not do it properly all the time, especially when properly equals easily?

Complete tosh.
If you watch some working boats somewhat bigger than yours being manouevred in a small space, they won't be fannying around with prop walk. They may be using manual force.

 

[adwuk]

Our boat has the prop nearer the centre point between bow and stern. The rudder is nine feet from the prop. The prop points down below the rudder. When you engage astern the prop does not ‘pull’ the boat astern but tends to result in the boat deciding what to do. We’ve had her for 11 seasons; I’ve never managed to work out how to deal with it. The only rough rule of thumb is that more than 50% of the time the wind will blow the bow downwind. But not always. Best thing is to let her do what she wants to do and try to sympathise. I’ve learned that the best approach is to be totally chilled and pretend everything is just fine. Panicking results in more bad behaviour from the boat.

I have three routes out of our berth, and always let our Nic make the first move before deciding which one I will use. Gives me the upper hand!

 

[johnalison]

Complete tosh.
If you watch some working boats somewhat bigger than yours being manouevred in a small space, they won't be fannying around with prop walk. They may be using manual force.

Watching working boats is well worthwhile, ferries, fishermen and excursion boats. I spent a long time watching a German trip-boat coming and going. It was a heavy old wooden thing of about fifty feet. Turning to leave involved exactly four to-and-fros each time with the helm kept in one full-across position.

 

[dom]

Manhandling a boat at any time smacks of incompetence, more so if using guard wires and stanchions. It is a worthless technique with 20 tons of vessel or 30 knts of wind. Why not do it properly all the time, especially when properly equals easily?

Cos the right way is different for the QE2 and an SB20! Nothing wrong with manhandling light boats.

Fully agree with your guardwires and stanchions comment unless gripped close to their bases.