The Low down of Mooring lines?

YachtNews · 10-19-2006, 11:35 PM

This is something i always wanted to know about. Why yachts, or most yachts while alongside, have their mooring lines so slack. Do they become slack or they just purposely ties them like that. ...Any ideas to help me?

Billy1119 · 10-20-2006, 12:03 AM

Well, it depends on the tides mostly. When you tie up the boat, you have to have the lines adjusted to allow for the hight change in the tide without making the lines too loose or too tight. This is dependent on many things, including the length of the lines between points were they're secured, the height of the dock/cleats relative to the waterline (and the deck), the amount of tidal change, etc. So, most of the time they are (should be) tied with enough slack to allow room for tidal increases. At high tide, you would generally want to tie the vessel tighter so when the tide goes out, the lines are not excessively loose. There are certain situations where this can be difficult, and the best way to keep things in place is frequent adjustment. Most of the time, however, if done correctly, you can have enough line for the tide, but not more than necessary.

Also, over time, especially when wet and tight (or have tension put on them), the lines will stretch on their own. They should be adjusted as necessary if this occurs to keep things in place properly.

On the other hand... I have often seen boats large and small tied up with poorly adjusted lines where it seems to me they just didn't know what they were doing. This is far too common from what I've seen...

YachtNews · 10-20-2006, 12:23 AM

Wow, thanks for you info, Bill...so how comes then cruiseships tie with so much tension then...i know i should not be comparing yachts and cruiseships but i see this....some container ships too...tide woulndt be a factor with these vessels too?

Billy1119 · 10-20-2006, 12:37 AM

No problem.

While I'm not cruse ship expert, here's what I suspect. The tides certainly affect them as well, but it doesn't play as big of a role because of the extreme length of the lines. When the tidal change is 3-4 feet, and the lines are tied onto the boat 50 feet from the pier, the tidal change has a relatively smaller affect on the line tension. In addition, I suspect the difference can just be stretched out of those lines because of their length (although I don't know if that's what they do).

It would be important to keep the ship carefully in place relative to normal boats largely because of the importance of it sitting still. Think of the passengers coming on and off, and cranes (or whatever) loading and unloading cargo, etc. If a slight breeze were to come along and it wasn't tied tight, someone or something could get hurt/damaged... There's also a lot more momentum that can be created when those suckers move around and could cause more damage.

This is what I suspect. In addition, because of the man power on these ships, perhaps they adjust the lines frequently enough to keep them tight, but not too tight (not forcing them to stretch).

Innomare · 10-20-2006, 04:21 AM

Hi Yachtluver,

modern cruiseships are normally equipped with automatic mooring winches. You can set the (range of ) required tension and they will pull in or let out the mooring lines to have the correct tension in the lines at all times.

Bruno

YachtNews · 10-20-2006, 01:07 PM

Thanks for your information Bill and Bruno, i know that cruiseships have Mooring winches.and even if i didnt know...i would be safe to assume there is some machinery being enabled to keep the lines so tight. but i is just that i didnt know how comes they were so tight in relation to the tidal change...I am an avid cruiseship enthusiast...just i didnt know that part.

What about the thicknesses of these ropes.....i remember when i was alot smaller and my dad used to take me into the Bridgetown harbour, i would see ships with lines that were almost or more than 7-8 inches wide... now yachts and ships use lines that are so small as compared...what are these new lines being made of that they can be so small now...nylon?

YachtNews · 10-26-2006, 12:28 AM

can anyone help me with the above question or i have to do my own research

?

Billy1119 · 10-26-2006, 12:54 AM

Quote:

Originally Posted by yachtluver

can anyone help me with the above question or i have to do my own research

?

Yeah, sorry about that yachtluver. Sometimes we just get tired of answering questions for certain individuals.

You are correct that one of the most popular materials for lines is nylon. I honestly don't know if that's what the big ships use, but I would assume as much. The two main variations are three-strand nylon and braided nylon lines. Three-strand generally will stretch more and isn't quite as strong as the braided, which tends to stretch less than three strand. Three-strand is cheaper, however, and is often used for anchor line on smaller boats because it stretches more, and can be easily spliced.

Some other materials are polypropylene (normally yellow), which serves its purpose, although you wouldn't want to use it to tie up your yacht. This kind of line floats. Dacron line will not stretch, but I don't know much about its other properties. Then there's the good ol' natural fiber, which I suspect is what the large 7-8" lines you mentioned were made of. This is not as strong as nylon and will rot much more easily.

Hope this answers your questions. I was, of course, kidding about getting tired of answering your questions.

Time for bed now, have a good night!

YachtNews · 10-26-2006, 09:50 AM

LOL...ok...i once thoughth that the thicker the rope...the stronger ( that was when i was 8 years old)... No wonder the thick ropes (natural fibres as you call them) pop so many times in the past....I know of a guy that was injured by one of those thick ropes that broke from a cruiseship here.

Garry Hartshorn · 10-26-2006, 04:01 PM

Many but not all large ships use wire cable especially if they have a self adjusting system.

YachtNews · 10-27-2006, 12:10 AM

Yea i realise Garry..

Now what about actual mooring with these lines. On yachts that berth stern first especially at marinas it is common to see them 'crossing' lines like in an X and then using two other lines that go outward from the main deck at the stern. Is there any particualar reason? why this method of tying?

Garry Hartshorn · 10-27-2006, 08:55 AM

Well the lines going directly from the tacht to the dock hold the vessel in and the crossed lines, springs restrain the vessel from surging along the dock.

YachtNews · 10-28-2006, 11:13 PM

SO what happned here with the Amels GU lines in this photo here taken by fellow member Stroepel. The aft line from the Port side is taught but the line a beam on the Starboard side is Very slack and looks to be serving no purpose really?........http://sports.webshots.com/photo/288...95209377AHlfFe

aeronautic1 · 10-29-2006, 01:06 AM

Quote:

Originally Posted by yachtluver

SO what happned here with the Amels GU lines in this photo here taken by fellow member Stroepel. The aft line from the Port side is taught but the line a beam on the Starboard side is Very slack and looks to be serving no purpose really?........http://sports.webshots.com/photo/288...95209377AHlfFe

The second "crossing" stern line is a back-up line and therefore does not need to be taunt. If you were tying up a 20 million dollar yacht, you would put out a few extra lines as well.

YachtNews · 10-29-2006, 10:17 AM

True True Aeronautic1---I thought GU cost more than that...None the less a great design by Amels...I wish they would build more yachts along a design like Gu.

Anyhow, my next question.....or more out of curiosity. Seeing numerous pics of yachts berthed at the IYCA....marina in Antibes France with the yellow mooring buoys...I see the larger yachts such as Carinthia VII, Constellation(stargates' sister) and so on tied onto the buoys. Out of curiosity, they usually have to let out alot of rope from the midships rope eyes( dont no the correct term for them) to tie to a buoy that is off to the front. Is this as stable and secure as dropping anchor at the bow?..I dont know if i am getting what i want to ask come out...