Bayfield 29 Refit Planning: Anchor gear (Part 2: The Rode)

Posted on by

The gears continue to turn as I further contemplate ground tackle…

While I’m still working through the options on an anchor selection (I’d like to get it done by October 15th in order to take advantage of the Boat Show Specials at Defender), I believe (read: hope) selecting the rode should be a bit less troublesome.

West Marine suggests that 1/8” of line diameter for every nine feet of boat length is appropriate. For a 29 foot boat this suggests a little more than a 3/8” line, or round up to 1/2”. Anchor chain would typically be half the size of the line, or 1/4”.

Rocna recommends 1/4” high test for their Rocna 10 (the recommended size), and 5/16” high test for their Rocna 15. Presumably the other anchors would benefit from similar sizing.

With agreement from two sources, if I go with a recommended size anchor, I’ll probably also go with 1/4” high test, upsizing slightly to 5/16” if I oversize the anchor. Although the larger chain isn’t that much heavier or more expensive and might be worth considering if I even think I might upsize sometime in the future.

How much chain and how much rope on the rode?

The general rule of thumb regards scope is 7:1 for the typical short length of chain followed by rope, and 5:1 for all chain rode. In heavy conditions as much as 10:1 might be called for, and in tight anchorages many people lie to as little as 3:1 ( hopefully all chain). It is important to remember to include the height above the waterline of the anchor roller and the expected tide in the scope computation (10 feet of water + 4 feet of freeboard + 2 feet of expected tide increase would equal 16 feet for the purpose of figuring scope).

I figure that 100′ of chain would allow me to lie to all chain at a 5:1 scope in fifteen feet of water (plus four feet of freeboard). Add 200′ of anchor line and I can anchor at 7:1 in thirty-five feet of water or 5:1 in fifty-five feet, which should cover me in most anchorages I’m likely to find myself in. Any more than that and I’ll have to add another length of line to the rode.

Freeboard: 4 Feet Chain Length 100 Feet
Draft: 3.5 Feet Rope Length 200 Feet
Water Depth Total Depth Scope
3 4 5 6 7 8 9 10
5 9 27 36 45 54 63 72 81 90
10 14 42 56 70 84 98 112 126 140
15 19 57 76 95 114 133 152 171 190
20 24 72 96 120 144 168 192 216 240
25 29 87 116 145 174 203 232 261 290
30 34 102 136 170 204 238 272 306 340
35 39 117 156 195 234 273 312 351 390
40 44 132 176 220 264 308 352 396 440
45 49 147 196 245 294 343 392 441 490
50 54 162 216 270 324 378 432 486 540
55 59 177 236 295 354 413 472 531 590
60 64 192 256 320 384 448 512 576 640
65 69 207 276 345 414 483 552 621 690
70 74 222 296 370 444 518 592 666 740
Anchor Chain Size WLL Weight/ft (pounds) Feet Total Weight (pounds) Price/Ft (Defender 10/8/12) Total Price
Acco G4 1/4” 2,600 0.64 100 64 $2.84 $284.00
Acco G4 5/16” 3,900 0.93 100 93 $3.76 $376.00
Anchor Line Size Average Tensile Strength Weight/ 100 ft (pounds) Feet Total Weight (pounds) Price/Ft (Defender 10/8/12) Total Price
Sampson Pro-set 3 strand 1/2” 6300 6.5 200 13 $0.57 $114.00
Sampson Pro-set 3 strand 5/8” 10000 10.5 200 21 $0.94 $188.00

Feed from: http://continuousmoon.blogspot.com/

4 thoughts on “Bayfield 29 Refit Planning: Anchor gear (Part 2: The Rode)”

Whatcha thinkin'?