proper pendant size

Knuttle · Dec 16, 2013

To determine the proper docking lines, you need to know the length and displacement of the boat. You also need to know what the conditions are in the docking area. While the first thought is natural wind and wave conditions, these can be significantly be changed by a lot of boat activity and their wakes.

These sites give the recommended lines for various boat sizes. Remember this is given per boat lengths, but you would not use the same lines for a 21', daysailer as you would for a deep draft boat of 21'

http://www.boatus.com/boattech/casey/docklines-casey.asp

http://www.westmarine.com/webapp/wc...reId=11151&page=Dockline-Upgrade#.Uq-e3LQt62U

Note the information about chafing and other elements in rope destruction. Chafing can also have other effects. When I bought my boat, the dealer had just received a load of boats from Los Angeles a trip of about 3000 mile, on one of the boats a chain had rubbed the hull the whole distance and there was a hole in the cabin about a foot long and went into the deck another 6".

Once you get the dock lines you will also need decent size bumper and other protective devices to keep the boat off of the dock structure and pilings

MrBill_FLL · Dec 17, 2013

Chafe is always the bigger problem IMHO.

3/4" would be too thin for me.

Around here you can get 1" 3 strand nylon at home depot, and 2" (IIRC) yellow polly for the floating portion.

How deep are you going to be anyway?
(going to 2" would cost how much more? How often are you going to dive the rode to check )

Knuttle · Dec 17, 2013

"1" 3 strand nylon for a 26' boat that weighs 3000lb +/-"
Way over kill. That would be about 4 times more rope that necessary. I don't think I have ever seen a 26" boat with lines that large.

The weight of 2" would weigh more than the of the empty boat ;-)

If you google "recommended dock lines" you will find most places recommend about half inch twisted nylon for dock lines.

While the absolute breaking strenght is important equally important is the elasticity of the rope. For line on a boat you want the lines to be able to hold the boat, but also absorb the force of the boat bouncing around. This elasticity thing is why it is recommended to have a length of chain between the anchor and the line. When pulled the first to give will be the chain coming off of the bottom and then the rope will stretch.

If you are having trouble making the selection there is one person who will give you the absolute. Contact the company who has your boat and boat liability insurance. They are going to have to pay off if there is damage to the boat because of failure of the docking and anchor lines.

Otherwise accept the recommendation from the rope manufactures and the books on sailing and boat handling. These things have not significantly change in 100 years

MrBill_FLL · Dec 17, 2013

mick hodapp said:
thank you for the reply.
i am going to be moored in 140ft at high tide. i would like to know what the proper size & material type line to use from where it will attach to the botom of the mooring buoy & then connect to the bow cleat. i will also run a 2nd line a couple of feet longer than the 1st line that will connect to the anchor line & then to the bow eye as a safety measure.
my 1st line will be 2-1/2 times my freeboard distance. we have the anchor (concrete & re-bar) weighed in at 2,600 lbs. any info would be appreciated !

you mean the top, or high part of the floating part of the buoy, correct?

3/4" poly is what I would use, or thicker. maybe 25', or more, but not interfere with any other boats swinging. (20-25')

Then run your bowline through a spliced eye and back to your bow cleat.
ex:
http://www.fla-keys.com/img/boating/FK_moorbuoy.jpg

OTOH, that will chafe too.... how long will it sit unattended?

I would not use the bow cleat, even if it was replaced with a metal cleat and properly backed...
I would use trailer tow eye, that is closer to the waterline,- but it needs to be re bedded if not already. mine was pretty loose and was starting to pull out. Some people have 2, for a safety.

140' is pretty deep. is it chain from the buoy to the bottom?
Who checks that? and how often?

You plan to drop your anchor in 140' + use the mooring buoy?
How much scope for the anchor? and do you think that might wrap around the mooring chain?

Honestly I would re post on the main board. people in the NE will have a lot more experience with moorings.

Knuttle · Dec 17, 2013

The short line from the bow to the buoy should be equivalent to the anchor line its self. Remember the old saying "A Chain is only as strong as its weakest link." This applies to the anchor line also.

You have a lot of valid concerns. If it were me I would find a book on anchoring and boating like "Chapman Piloting: Seamanship & Small Boat Handling"

http://www.amazon.com/Chapman-Piloting-Seamanship-Small-Handling/dp/0688148921

Chapman's is the best. You can get some older revision for a modest price. (Remember a boat responds to the ocean the same to day as it did a thousand years ago, so old is not bad, like in computers )

Another is The "Annapolis Book of Seamanship". I know part is available online. I don't know if it is complete. Search Google books for the above name.

I would also go to the local boat dealers, (not Walmart and the like) and talk to them about what you plan to do and what they recommend. Those local boat yards and dealers have the most experience with moorings in the area you are planning to keep the boat.

PS: 140 foot tides? Where are you planning to keep the boat?

centerline · Dec 17, 2013

to go from the bow cleat to the mooring ball on a macgregor boat that is left unattended for an undetermined amount of time, I would use a 15ft long peice of 5/8" double braid, with a thimbled eye around a moused hook on one end to attach to the mooring ball, a piece of leather chafing gear over the rope (or heater hose works good too, if you want to do it on the cheap) and then snub the tail end to the cleat.... I would NOT use a loop or eye thrown over over the cleat, but actually snubbed to the cleat

the 5/8 rope will drag the mooring anchor (im sure that 1/2 double braid would do it), and the 5/8 is also strong enough to pull the bow cleat out of your boat, and at the same time its big enough to allow for some chafe before it would weaken enough to fail.

on a mooring ball you are not supposed to let out scope, as the system is set up with a heavy anchor, and the buoy riding on the water is the cushion for wind and wave action... and if everyone wants to let out scope, whats the point of a mooring ball?

depending on where you are, the mooring balls are sometimes so close together that about a 20 pendent is all you can safely let out without getting real cozy with your neighbor boat..

the size of the 5/8 will look better than 1/2", and it has alreay been said, its the weakest link that will usually fail, so it could be that the actual chain holding the mooring ball to the anchor is what has the weakest link, as they do corrode and wear.

so you just dont need any bigger line for the job

MrBill_FLL · Dec 18, 2013

Double braid would work, with a float on it. otherwise hard to pickup with a boat hook. (it sinks)

chafe is the problem, IMHO..

Centerline, when you say heater hose, do you mean a car's water heater hose (rubber)
or something else?

I know practical sailor did a chafe test on garden hose over 3 strand... results were not good for that, but leather and fire hose worked well. as did some cloth selves made for this.