Coming alongside pontoons....

[Big-Bang1]

Hi!
Out last weekend and watched a couple of chaps coming alongside a pontoon. All the boats already on the pontoon were facing into the tide although the breeze was in the opposite direction (Which is how I've always come alongside as it keeps a flow of water over your rudder to maintain steerage). But after a failed attempt they went around and eventually came alongside. Is there something I'm missing? Was there a good reason for going alongside stern to the tide?

 

[mainsail1]

Nope, not a good idea.

 

[dom]

I do this a lot. It is just as easy to ferryglide in with the tide flowing from astern as from the bow - at least in boats that reverse well it is. One can then set the boat up for an uptide departure depending on times.

 

[nortada]

Hi!
Out last weekend and watched a couple of chaps coming alongside a pontoon. All the boats already on the pontoon were facing into the tide although the breeze was in the opposite direction (Which is how I've always come alongside as it keeps a flow of water over your rudder to maintain steerage). But after a failed attempt they went around and eventually came alongside. Is there something I'm missing? Was there a good reason for going alongside stern to the tide?

Wasn’t there so don’t know.

Handling characteristics and weather conditions can dictate various strategies.

Their first approach could have been to gauge conditions before a successful arrival. Could have been a demo or a bet - lots of possible reasons.

 

[capnsensible]

I do this a lot. It is just as easy to ferryglide in with the tide flowing from astern as from the bow - at least in boats that reverse well it is. One can then set the boat up for an uptide departure depending on times.

Yeah, its quite straightforward on an AWB, isnt it. Can be useful in wind against tide (tide is king!) so the wind and rain doesnt honk in to the saloon whilst you are alongside too!

Its a favourite for YM examiners when inviting candidates to demonstrate their boathandling skills too. :encouragement:

 

[jac]

Depends on breeze , boat as well. It may be that her head blew off os by berthing stern first with the bows down wind they had more control.

 

[Simondjuk]

I think there may be some confusion as to whether they're being described as having gone alongside ahead, downtide and upwind or astern, uptide and downwind.

 

[mainsail1]

I am amazed at some of the comments here.
The most controlled and successful way to come alongside is heading into the tide.
Trying to come alongside down tide is sometimes possible but can end in tears, especially if a wind is blowing you off the pontoon or the tide is strong and catches the wrong side of the keel.
It is all down to the flow of tide against the keel and across the rudder. Heading up tide the tide pushes the keel towards the pontoon as you angle the boat towards your destination and tide over the rudder gives steerage way long after it would be lost going in down tide.

 

[capnsensible]

Dont be amazed, there is always more than one way to skin a cat.

Anyway, looks like I read the OP wrong! Im advocating going astern into the tide stream as easy on an AWB.

 

[TLouth7]

The most controlled and successful way to come alongside is heading into the tide.
It is all down to the flow of tide against the keel and across the rudder. Heading up tide the tide pushes the keel towards the pontoon as you angle the boat towards your destination and tide over the rudder gives steerage way long after it would be lost going in down tide.

But if you approach facing downtide but moving in reverse then all the effects you describe are just as true, the only difference being that the boat is moving backwards (which I concede is harder to control for a lot of boats).

Maybe the first attempt wasn't a failure, they just decided that it was too easy and took the opportunity to practice a slightly harder manoeuvre in benign conditions.

Or maybe they have a gate in the guardwire on one side, and so prefer to have that next to the pontoon.

Or maybe the uptide approach to that particular space was obstructed.

The point being that while coming alongside facing uptide is conventional, there are plenty of valid reasons to deviate, but you should be aware of the difficulties this will impose.

 

[jac]

I am amazed at some of the comments here.
The most controlled and successful way to come alongside is heading into the tide.
Trying to come alongside down tide is sometimes possible but can end in tears, especially if a wind is blowing you off the pontoon or the tide is strong and catches the wrong side of the keel.
It is all down to the flow of tide against the keel and across the rudder. Heading up tide the tide pushes the keel towards the pontoon as you angle the boat towards your destination and tide over the rudder gives steerage way long after it would be lost going in down tide.

Very true - My comment was making the assumption that they moored heading into the tide stern first. Not clear from the OP.

As an aside, I grew up in Norfolk and it was always a lesson on the lower River Yare to see some of the tourist boats attempting to moor at riverside pubs and forget the tide. Usually be a chorus of cheers after the bang in the same way that a dropped glass in a crowded pub gets a response!

 

[BelleSerene]

Nope, not a good idea.

It’s a fine idea. You may be confusing moving in the direction of the tide, with the boat pointing into the tide. The OP is describing a reverse ferry glide: still moving into the tide, just stern first.

This is often better than ferry-gliding forwards, because you get more control. By putting the rudder to one side, you can angle is the boat to the tide and by keeping it amidships you maintain that angle of ferry glide. When you’re against the dock you can use the rudder in the same way to keep you there, giving you more time to make fast - whereas with a forward ferryglide, a strong tide can get between the boat and shore and force you seaward again. (That’s if you are tying the stern first, which I tend to do when single-handed.)

You do need to keep the angles small, as it’s easier than in a forward ferryglide to get into an unstable situation where you can’t overpower the tidal moment on the boat.

 

[dom]

I am amazed at some of the comments here.


It is all down to the flow of tide against the keel and across the rudder. Heading up tide the tide pushes the keel towards the pontoon as you angle the boat towards your destination and tide over the rudder gives steerage way long after it would be lost going in down tide.

It can be easier to think about what's going on in simple vectors. If a tide is say running at 2 knots parallel to the pontoon, one can stem the flow by either nosing or reversing into it at 2kts. One can then proceed from that stable equilibrium.

The operation of the foils is largely symmetrical, subject to the usual boat handling differences in reverse: pivot point further aft, control surface become a leading-edge as opposed to a trailing-edge, different foil profile, etc. But nothing different to reversing normally.

What often matters more is getting off, esp for racing and other boats with folding props and no thrusters. If the tide is flowing directly from behind, one typically springs the stern off to open the foils to the tide, then hit reverse to prevent the boat being pushed forward. Folding props (like mine) can be foodmixerish in reverse, so departing forwards in these circumstances is much easier.

All in all, I think it depends on the circumstances: certainly if tide and wind from same direction, reversing-on can be a dream. Why, if Mr Sensible was examining us in such circumstances he'd probably be thinking we parked Cunard Liners for our day jobs

 

[capnsensible]

Going back (!) to ahead, downtide, is very occasionaly something Ive had no choice with. So the odd practice can only be a good thing. As long as you arent going at the same speed as the water, you got rudder, even if its limited. A centre cleat with midships line are very good under such circumstances.

 

[capnsensible]

It can be easier to think of what is going on in simple vectors. If a tide is running at 2 knots parallel to the pontoon, one can stem the flow by either nosing or reversing into it at 2kts. One can then proceed from that stable equilibrium.

The operation of the foils is largely symmetrical, subject to the usual boat handling differences in reverse: pivot point further aft, control surface become a leading-edge as opposed to a trailing-edge, different foil profile, etc. But nothing different to reversing normally.

What often matters more is getting off, esp for racing and other boats with folding props and no thrusters. If the tide is flowing directly from behind, one typically springs the stern off to open the foils to the tide, then hit reverse to prevent the boat being pushed forward. Folding props (like mine) can be foodmixerish in reverse, so departing forwards in these circumstances is much easier.

All in all, I think it depends on the circumstances: certainly if tide and wind from same direction, reversing on can be a dream. Why, if Mr Sensible was examining us in such circumstances he'd probably be thinking we parked Cunard Liners for our day jobs

Well Im not an examiner, I prepare candidates and what on earth has that got to do with Cunard Liners???

 

[neilf39]

I would nearly always go alongside into the stream unless it was very weak. Boat has bilge keels with stern hung rudder. The bow will blow off quicker than the stern. In reverse I find the ruder is not as effective as it is going forward, also the prop is not putting any wash over the rudder. However it does all depend on what the angles between the wind and tide actually are and also, if there is rafting on both sides, which is the easiest direction to get in the gap. Matter of knowing how your boat handles and assessing each situation as it arises.

 

[capnsensible]

BelleSerene, I am afraid you are wrong. Wrong is not a word I use lightly as there are usually many different ways of doing the same thing well but not in this case. It is all about the action of the tide against the keel and the rudder as I explained.
When going alongside stern to the tide you are an accident waiting to happen.

Just so Im understanding this, are you saying that you cant go astern into the tide and dock port or starboard side to without having an accident??

 

[dom]

Well Im not an examiner, I prepare candidates and what on earth has that got to do with Cunard Liners???

Just an impression: I love the way these big ships (usually!) saunter up to their berths, then slide in gracefully and effortlessly as mooring lines are accurately dispatched from the ship.

By comparison, us yotties tend to engage in a lot more crashing, banging, leaping and swearing

I say usually, because some like the QE2 with undersized thrusters can be more like us lot in the absence of a friendly tug :ambivalence:

 

[dom]

BelleSerene, I am afraid you are wrong. Wrong is not a word I use lightly as there are usually many different ways of doing the same thing well but not in this case. It is all about the action of the tide against the keel and the rudder as I explained.
When going alongside stern to the tide you are an accident waiting to happen.

You've got it; I am afraid you are wrong

 

[TLouth7]

I see three options being considered in this thread:

1 - approaching forwards, bow into the tide. This is the classic approach, as we generally prefer moving forwards, and can end the manoeuvre stationary relative to the pontoon while still moving forward relative to the water, thus maintaining steerage throughout.

2 - approaching in reverse, stern to the tide. Most of us would find this harder as we are not so good at steering in reverse, but it may offer advantages. For example if the wind is with tide this will stop the bow being blown off; it may result in correct orientation for leaving; if singlehanded it brings the stern in first so the helm can drop a bow spring onto a cleat and then step off the quarter with a stern warp.

3 - approaching forwards, stern to the tide. This is the least preferable, but still potentially valid in certain circumstances. The problem is that to maintain steerage you must keep moving forwards relative to the water, so you arrive at the pontoon moving at tide + steerage speed. With enough length of clear pontoon a skilled crew member should be able to bring you to a controlled stop. It may be difficult to hold the boat against the pontoon with a bow spring in this situation, so getting a stern warp on will be a priority.

It is not clear from the OP's post whether they are referring to option 2 or 3.

For what it is worth, I think that a lot of problems in berthing stem from transitioning from 3 to 2 while close to the pontoon. There is inevitably a loss of control as you move from forward to reverse (relative to the water), so it is better to make this change with plenty of space.

Edit: Punctuation