Effectiveness of anchor chain weight versus, length!

[MathiasW]

With regards to the energy dissipated by a chain getting dragged through water, have a look at this great experiment of a chain getting dragged through water:

Possibly Original Thought About Chain Catenary - or - The Myth of the Bar Tight Chain - Page 2 - Cruisers & Sailing Forums and scroll down to post #30.

One would need to do the maths more precisely, but it seems the energy dissipation in a typical case can be of the order of 100 Joules or so per swing (of the anchor chain) through the water. This is a sizeable fraction of the swell energy, but usually not dominating it, and a snubber seems to be more effective, still.

 

[thinwater]

With regards to the energy dissipated by a chain getting dragged through water, have a look at this great experiment of a chain getting dragged through water:

Possibly Original Thought About Chain Catenary - or - The Myth of the Bar Tight Chain - Page 2 - Cruisers & Sailing Forums and scroll down to post #30.

One would need to do the maths more precisely, but it seems the energy dissipation in a typical case can be of the order of 100 Joules or so per swing (of the anchor chain) through the water. This is a sizeable fraction of the swell energy, but usually not dominating it, and a snubber seems to be more effective, still.

Yup.

Another way to consider this, is that the drag due to moving a chain vertically through the water is not very different from a similar strength rope (you can check the maths or you can measure it). If you pull the slack out of a similar size rope, how much load is that? In fact, you can do this in a few seconds by hand without straining. Common sense, but you are welcome to test it.

Or you can look at the published work of people like Neeves (and me), who used load cells and generated data very similar to some of the better calculators. In fact, the system is very chaotic. Much depends on how wave impacts, gusts, and yawing swings interact. When they coincide you can get a real thump, the coincidence overwhelming the effects of friction and hull damping.

Get a load cell and record numbers. Then you will know about YOUR boat.