Mooring lines, tight or slack?

[ctva]

As long as you are using mooring warps, not old genoa sheets, then they should have enough stretch in them and you'll be fine...

Whenever I hear creaking mooring lines they are static ropes, old sheets, halyards etc..

If proper dynamic stuff is used, then there is plenty of stretch and I've never had any creaking from the octoplait warp I use. Plenty of stretch. I always tie the boat up so that it will sit about a foot off the pontoon when being blown off. 'Snatch' loads of this size are small and mostly absorbed by the warp. Anyway when the boat is tight it means that there is permenant pressure on the fenders with resultant danger of popping out and scuff marks on the hull.

 

[Nostrodamus]

I didused to be a member of a club that was very anal about the way boats should be moored. It was always, one rope for one job, always tie on with round turn and two half hitches on a cleet, spring fixed so that they are on two cleets on the boat to one one the pontoon, never the other way round, no spare line left on the dock, never use a mooring line with a built in loop.
Now there are somethings I agree with but when the boat was being blown of or being held off by the tide it used to take forever to get it just right. Alo comming back to the boat it took a long time to undo everthing and double it up ready to leave (by using springs of course, never pushing the bow or stern out).
These wee club boats so it was difficult to argue.

Should mooring lines go inside or outside the fenders?

 

[Elessar]

We put slack in all the lines. As said it reduces the loadings on cleats.

Slack line = higher peak loading.

 

[Babylon]

I've learnt something here, thank you

I didused to be a member of a club that was very anal about the way boats should be moored. It was always, one rope for one job, always tie on with round turn and two half hitches on a cleet, spring fixed so that they are on two cleets on the boat to one one the pontoon, never the other way round, no spare line left on the dock, never use a mooring line with a built in loop.
Now there are somethings I agree with but when the boat was being blown of or being held off by the tide it used to take forever to get it just right. Alo comming back to the boat it took a long time to undo everthing and double it up ready to leave (by using springs of course, never pushing the bow or stern out).
These were club boats so it was difficult to argue.

I can't argue with that, as it seems very sensible, especially as they were club boats an not your own.

Coming alongside initially, securing a boat properly for an extended period, and setting up slips (or 'doubling' if you prefer) for later departure are three completely separate exercises. I'd certainly make the effort to secure everything properly (and neatly), including adjusting warps and springs so that they'll function for all states of tide and wind conditions when I'm away. You also never know what wind or tide you'll need to deal with when you're back and ready for the off, so preparing slips (and springs if need be) will always be different.

I tend to use bowlines over cleats (or through the eyes and then up and over the horns), but the merits of a round-turn and two half-hitches are that they are more resistant to chafe and can be undone under load. I think I'll do that in future.

 

[Nostrodamus]

If the boat was being left I would agree and it has always stood the test of time but when the next crew are waiting on the pontoon to take over and you still have to tie it up in the same manner?

 

[puddock]

I was tied up alongside in a port last weekend. I had the springs fore and aft tied up tight to a the quay side near the bow and near the stern. The bow and stern lines were a little slack.

I got woken up in the night. The boat was charging backwards and forwards by a good 4m. It seems the oscillation frequency of the springs coincided with the wave frequency. The waves were only a few centimeters big!

I moved the boat back a bit so the springs were of unequal length. This seemed to dampen the motion a lot. But I was now well clear of the nasty big black tyre hanging off the wall for the fishing boats and it was raining, so I really could not be bothered after that.....

I would seriously advise, in that situation (ie harbour walls etc) to disregard springs and use as long bow and stern lines as you can. The boat will then 'lie off' by a metre or two from the wall and surging will be eliminated. Take a look at the fishing boats in your local harbour next time you're there. Obviously any wind blowing you onto the wall would affect you differently.

 

[westernman]

I would seriously advise, in that situation (ie harbour walls etc) to disregard springs and use as long bow and stern lines as you can. The boat will then 'lie off' by a metre or two from the wall and surging will be eliminated. Take a look at the fishing boats in your local harbour next time you're there. Obviously any wind blowing you onto the wall would affect you differently.

I would be concerned about the maximum possible movement backwards in my precise situation without using springs - I had an expensive gin palace parked stern to the wall about 6m off my stern. The shore bollards were not ideally placed - a fair way ahead and behind me. The wind was light and blowing me onto the wall.

 

[KellysEye]

>How does it reduce the load on the cleats?

If you tie the lines tight there is no stretch. Thus peak load on the cleats all the time. Loosened lines allow stretch thus the load is applied slowly. Of course the boat's momentum will slightly increase the load but it's intermittent We often see boats tied with old sheets rather than rope, you should see how they snatch with no stretch.

 

[MapisM]

Slack line = higher peak loading.

Spot on.
No matter how tightly the lines are secured, the static load will always be ridiculous compared to the potential peak load, wihch can be impressively higher - particularly with wind gusts and heavy boats.
Lines must be ALWAYS as tight as possible, unless tide enters into the equation. But this wasn't the aim of the original question, as I understand it.

PS: has anyone ever seen a ship moored with loosened lines?

 

[Robin]

PS: has anyone ever seen a ship moored with loosened lines?

No, but then I've never seen a ship in a marina berth either. Tied to a quay or a wharf is an entirely different situation.

Imagine no wind and no tide, but a gentle swell/ripple in the berth. Put a cork in the water and it will move in a cycle to match the wave form, forwards, up, back and down in an elliptical movement, but not moving outside of that to go farther forwards or farther backwards. So if nothing changed at all, no restraint is required, but that is perfection that never lasts. So allow the cyclical movement unrestricted but put limit lines on it in the form of spring lines and breast lines. The forward spring has to limit movement towards the pontoon, the bow lines both locate sideways position as well as acting in part as a back spring to prevent more movement aft than desired. the stern line aid general location in conjunction with the bow lines. As I said, personally I like to allow some elastic movement in the bow lines by the use of snubbers which keep the lines 'taut' but not rigid and allow some aft movement (limit set by a spring). A separate spring is the one which absolutely limits riding forwards beyond a set point, keeping the boat off the pontoon. An addition we also used was an extra spring on the non-finger side which was tight, this pulls the boat away from the finger most of the time.

A good example of allowed movement used to be in Plymouth Marina where swell can be severe, I believe car tyres are used (not been there in a while) in the lines in some berths to provide heavy duty snubbers.

 

[MM5AHO]

I use long tight springs and short loose bow and stern lines.
The long springs are at least half as long as the boat, one from stern cleat to pontoon cleat at half way or more, and same from bow backwards. These are tight to prevent for/aft movement along the finger, but being at such an angle from the pontoon (almost parallel to it), they have plenty of room for waves to cause rise and fall in the boat relative to pontoon.
The bow and stern lines are ony to prevent the bow or stern from coming too far away from the pontoon. If these are tight, then they can prevent rise and fall, so these are left quite slack.
Plastic hose over the toerail helps reduce chafe.

 

[snooks]

I tend to use bowlines over cleats (or through the eyes and then up and over the horns), but the merits of a round-turn and two half-hitches are that they are more resistant to chafe and can be undone under load. I think I'll do that in future.

But a RTTHH can work loose if left over a long period, and a bowline can be undone under pressure, all you have to do is loosen the other end so it's not under pressure

Worst comes to the worst you can always put another line on there temporarily while you undo the bowline.

 

[Elessar]

But a RTTHH can work loose if left over a long period, and a bowline can be undone under pressure, all you have to do is loosen the other end so it's not under pressure

Worst comes to the worst you can always put another line on there temporarily while you undo the bowline.

Bowline can come loose if the loop isn't under load - or worse is under intermittent load.

RTTHH less likely to come undone than a bowline on, for example, a dinghy painter.

An extra hitch on the tail of the bowline changes things though. Even so i wouldnt choose a bowline for mooring. After all you can make it slack by cutting it, but that doesnt make it preferred!

 

[whisper]

Alongside a quay

I would seriously advise, in that situation (ie harbour walls etc) to disregard springs and use as long bow and stern lines as you can. The boat will then 'lie off' by a metre or two from the wall and surging will be eliminated. Take a look at the fishing boats in your local harbour next time you're there. Obviously any wind blowing you onto the wall would affect you differently.

We have an alongside berth against a quay wall and do exactly as you say. Long fore and aft lines - ours are at least as long as the boat - tied to ring or chain on the wall - and relatively tight. Keep us in position, fore & aft, on the wall
Plus breast ropes that are relatively loose - until the water disappears anyway!!
Luckily the range is only about 2.5m.
System has worked well for a number of years.