|
I'd like to correct what I believe to be a misconception on stretch in dock lines. Stretch is really only desirable as far as tidal change is concerned. If it were not for change of tide I'd recommend wire rope. I know it's not practical. The point is that, when tieing up your boat you do not want it to move at all. It is the movement which is going to cause damage. In adequate number of lines as well as inadequate cleating are going to hurt you before stretch is a factor. Regarding cleating; doubling up on one cleat, while very common, is asking for trouble. If a cleat pulls out and you lose your breast line, the stern line may keep you adequately alongside. If your spring line was doubled up with the breast line on the same cleat you have now lost two lines, and allowed the boat to have a lot more movement.
I recommend dacron over nylon for dock lines as it stretches less and is more abrasion resistant.
I cannot emphasize the point of movement enough. If you look at a merchant ship or cargo secured on deck, or below, you will readily notice that there is no way the lines/wire rope are capable of lifting the vessel or the cargo. They are there to stop movement. Once movement starts, be it a diesel locomotive loaded on deck, or the ship alongside, you're done and it's just a question of how much damage will result.
The same point applies to dock side fixtures. If you have multiple lines running to a single cleat you are only as strong as the cleat and it's securing. Bollards and pilings make much better choices also as they are stronger than a cleat.
A common mistake made is to lead a breast line at too sharp a downward/upward angle to it's dockside fixture. As you walk along the dock you'll see breast lines leading from a vessel at a forty five degree angle down to the dock. With an off dock wind, these lines will part in a vain attempt to keep you alongside. Sometimes that lead is all you have, and may be suitable for benign conditions, but if weather is coming up lead them to the opposite side of the dock, acheiving a more horizontal lead and thereby using their full strength to hold you alongside.
One last item. The time to double up is well before the wind comes up. If your vessel has any significant "sail" area to hull and superstructure you are not going to winch her back alongside. Double up before she's laying two feet off the dock.
|