very basic; mooring to a harbour wall question.

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steve yates

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I cant seem to get my head round this.

q1) If I come alongside a harbour wall at high tide, tie up, and bugger off to the pub, how exactly do I arrange the mooring ropes and springs to cope with the 8m difference at low tide?
I can't leave 8m of slack or the boat will be all over the place, but if I snug her up tight, she'll be left hanging in air, suspended by her cleats, if I'm lucky!
Its obviously something done all the time by you guys, but I can't figure it out!

q2) With a large tidal rise and fall, on a small 18ft boat, for tying to a harbour what kind of length mooring warps and springs should I be looking at?
 
steve yates said:
I cant seem to get my head round this.

q1) If I come alongside a harbour wall at high tide, tie up, and bugger off to the pub, how exactly do I arrange the mooring ropes and springs to cope with the 8m difference at low tide?
I can't leave 8m of slack or the boat will be all over the place, but if I snug her up tight, she'll be left hanging in air, suspended by her cleats, if I'm lucky!
Its obviously something done all the time by you guys, but I can't figure it out!

q2) With a large tidal rise and fall, on a small 18ft boat, for tying to a harbour what kind of length mooring warps and springs should I be looking at?
Click to expand...

I've never had to tie up with such a large tidal drop but would have thought that whilst lines going from the boat straight across to the wall will soon leave the boat suspended, longer lines or springs going from the bow of the boat to the wall near the stern, or beyond, would have a lot more scope in them. Whether such lines could cope with 8m of tide is a different question. Perhaps you need to drink up a lot more quickly and get back to the boat. :)

Richard
 
sailorman said:
The internet is a great asset

https://duckduckgo.com/?q=how+to+moor+a+yacht+to+a+dock+in+tidal+waters&t=opera

http://www.tropicalboating.com/2010/04/tying-boats-to-docks-using-springlines

with 8 m tide i would stay o/b BUT would have to be DESPERATE to be alongside at all
Click to expand...

This is the internet.

I had already seen that, I'm hoping for more real world answers.
eg, the bit about tides says.."The only sure way to keep the line tension correct is to stay on board constantly monitoring and adjusting."

Thats no use to me, and doesn't explain all the boats left tied up to harbour walls for weeks on end. I want to know how they do it so I don't have to keep leaving the pub or my meal to check.

And the other link, (which is very good by the way, thx) says "It also helps to attach dock lines to cleats or pilings that are at the same level as the cleats on the boat at mid tide, if this is possible."

Again, ain't gonna happen with a harbour wall!
 
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The last time I spent a night on a harbour wall is was non-tidal, but it rained during the night and washed grit onto my fenders which ground their way into my gelcoat, so I've never done it again.
 
steve yates said:
This is the internet.

I had already seen that, I'm hoping for more real world answers.
eg, the bit about tides says.."The only sure way to keep the line tension correct is to stay on board constantly monitoring and adjusting."

Thats no use to me, and doesn't explain all the boats left tied up to harbour walls for weeks on end. I want to know how they do it so I don't have to keep leaving the pub or my meal to check.

And the other link, (which is very good by the way, thx) says "It also helps to attach dock lines to cleats or pilings that are at the same level as the cleats on the boat at mid tide, if this is possible."

Again, ain't gonna happen with a harbour wall!
Click to expand...
What responsible owner leaves his vessel unattended with that much range of tide :sleeping:

Good luck, you will need it :encouragement:
 
sailorman said:
What responsible owner leaves his vessel unattended with that much range of tide :sleeping:

Good luck, you will need it :encouragement:
Click to expand...

It seems to me, most fishing boat owners in small drying harbours.
Maryport has numerous fishing boats and a few leisure yachts tied up against the walls. None of those leisure craft have moved that I can see for the last 6 months.

I'm sure it's not unique?
 
steve yates said:
I cant seem to get my head round this.

q1) If I come alongside a harbour wall at high tide, tie up, and bugger off to the pub, how exactly do I arrange the mooring ropes and springs to cope with the 8m difference at low tide?
I can't leave 8m of slack or the boat will be all over the place, but if I snug her up tight, she'll be left hanging in air, suspended by her cleats, if I'm lucky!
Its obviously something done all the time by you guys, but I can't figure it out!

q2) With a large tidal rise and fall, on a small 18ft boat, for tying to a harbour what kind of length mooring warps and springs should I be looking at?
Click to expand...

Stretchy ropes and elementary trig. You have a bow and stern ropes which go several meters to the front and back of the boat - that way as the boat drops, the extension of the ropes isnt great. You have a centre cleat rope again with some extra length and tied at the watreline if you are coming in at high tide or a few meters up the ladder if coming in at low tide. You'll wander a bit but not much. Or at least thats what I do in the Bristol channel
 
steve yates said:
It seems to me, most fishing boat owners in small drying harbours.
Maryport has numerous fishing boats and a few leisure yachts tied up against the walls. None of those leisure craft have moved that I can see for the last 6 months.

I'm sure it's not unique?
Click to expand...


Maryport to the best of my knowlege does not have an 8 metre tide-in much smaller tidal ranges lines and springs can cope.

Not done it very often-I dont like to risk my topsides if I can take a mooring or anchor off. When I have taken the ground and leaned against a wall at the bottom of a tide I find it impossible not to be stressed out and fuss over the lines-both on the way up and the way down!
 
8m is nothing compared to the Channel Islands.

And yes many boats moor against the walls. As someone said, if you can get your lines wide, that helps but the answer is to come back frequently and adjust; there is no easy answer and no long term solution.
 
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The standard approach is to rig bow and stern lines to a length 4 times the tidal range and springs 6 times the range. The run along the wall so they have are almost parallel with the wall. In effect you would have 4 spring lines. These would keep the boat alongside without getting tight throughout the tide (in theory..). Fishermen do it all the time.

However....This is unlikely to be practical With a 8 m range as you'd need 50 m warps so as others say it's probably best to go somewhere else or stay on board and adjust as necessary, if you can be bothered with the stress.
 
Portpatrick harbour has this covered pretty well. I'll try to explain then someone will tell me a name for it. Taught Wire strops running vertically attached to the wall one end fixed above high water one end fixed below low water. They are fixed on a bracket that makes them stand out from the wall about 6 inches which allow your lines to run freely up and down. Moor up to the strops with with a loop around the strops. You can set springs as well to limit forward and backwards movement. There are also large round fenders running up and down the strops . As the tide rises and falls the loop around the strop rises and falls with the boat. It seemed to work very well when I was there. I'll try to find a picture.
 
A spare anchor sounds a good idea, doesn't it just bash the boat sides though?


rotrax said:
Maryport to the best of my knowlege does not have an 8 metre tide-in much smaller tidal ranges lines and springs can cope.

Not done it very often-I dont like to risk my topsides if I can take a mooring or anchor off. When I have taken the ground and leaned against a wall at the bottom of a tide I find it impossible not to be stressed out and fuss over the lines-both on the way up and the way down!
Click to expand...

From tide-forecast.com.. "Maryport Tide Chart. The largest known tidal range at Maryport is 8.98m 29.5 feet " Obviously not always, but today for instance high tide is 8.01m and low tide -0.55m.
 
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