I have a 29ft displacement launch. What diameter of anchor chain do I need. And what diameter of anchor rope?

Answer 1

The anchor line.

All of the gear, taken collectively, that lies between a boat and it's anchor is called the rode -- whether it be synthetic fiber, chain or a combination of the two.

Twisted nylon.

Nylon, in three-strand twist or double-braid form, is now by far the most widely used material for anchor lines.

For anchoring, perhaps nylon's greatest asset is it's elasticity; nylon stretches a third or more under load. It's working elasticity is 15 to 25 percent, which is of particular value when a boat surges at anchor in steep seas. In such conditions there is a heavy shock load on fittings and ground tackle -- unless provision is made to absorb it gradually. Nylon's elasticity does exactly that.

Some boaters unwittingly lose part or most of the advantages inherent in nylon by using too large a line. Within the limits of safe working loads, the smaller the diameter the better the elasticity for given conditions. A practical limit is reached when small diameters (though rated high enough for breaking strength) are not convenient to handle. Some experienced boaters use nylon as light as 3/8-inch diameter on working anchors of 30- to 40-foot craft.

...nylon line is highly resistant to rot, decay and mildew, but can be damaged by rust from iron fittings or chain.

Chain.

The three kinds of chain most used as anchor rode are "BBB", "Proof Coil" and "High Test." Chain is designated by diameter of the material in the link, but the links of the various types differ slightly in length. It is necessary to match the chain to the wildcat (a pulley designed for use with chain) of the anchor windlass; the differences in link length are slight, but enough to cause trouble if there is a mismatch.

BBB is marginally stronger than Proof Coil; High Test is significantly stronger than either. The selection of specfic chain type and size for your boat involves several factors, the first of which is adequate strength. A safe standard to use is a working load figured from the size of the boat and the conditions to be encountered -- at 20 percent of the chain's breaking strength when new. But you must consider weight. The chain must be heavy enough to provide a proper sag to cushion shock loads, but the length required for normal anchoring depths must not be so heavy, when stored on board, that it affects the boat's handling characteristics or even it's safety.

Nylon-and-chain.

Today the ideal rode is a combination of nylon line and a short length of chain -- 6 to 8 feet or longer is desirable -- between the line and the anchor.

One effect of chain in this combination rode is to lower the angle of pull, because chain tends to lie on the bottom. Of equal or even greater significance is the fact that today's lightweight anchors often bury completely, taking part of the rode with them...

Chain used in this way may vary from 1/4-inch diameter for 20-footers up to 7/16-inch for 50-footers.

Chain should be galvanized to protect against rust.
.........................................................................................

For a 29 ft. boat:

Rode Length -- 200 ft.

Rode Size ----- 7/16 inches

Chain Size* --- 5/16 inches

Storm Anchors model no.

Danforth 22-S

Fortress FX-11

Plow (lbs.) 25

Bruce (lbs.) 16.5

Delta (lbs.) 22

* Recommended chain length: 1/2 foot of chain for each foot of boat length.

This info taken from "Chapman Piloting", 62nd Edition
Copyright 1994, 1996 by The Hearst Corporation
Pages 257 -- 261.

http://en.wikipedia.org/wiki/Chapman_Piloting

http://search.barnesandnoble.com/booksearch/isbnInquiry.asp?z=y&endeca=1&isbn=158816232X&itm=2

Happy Boating!

.

Answer 2

the type of anchor you have will determine the size and type of chain and rode..a standard Danforth anchor for a 30 foot boat will need a 14 pound anchor that has a holding power of 920 pounds. chain dia. should be four inches minimum. ten feet of chain will be needed. you will need to go to a marine supply store . there are dozens of combi nations to choose from. the line should be at leeast 3/8" dia. of nylon. you can buy a complete assembly of anchor, chain and line to fit your boat.

Answer 3

25 lb anchor on 6m chain on 12 mm rope should be a good working anchor; 40 pounds on 3/8th chain and 3/4 line would be a good storm anchor..

Danforth, CQR, Bruce in that order on anchor selection

Answer 4

depends