Anchor leg

[RainAndStorm]

I'd like to ask if anyone's aware of a mechanism that attaches to the anchor and pushes down on the ground as the chain is pulled up?

The idea is simple:

• The said leg is made out of metal, ideally an inch or two wide, same length as the anchor
• It swings towards the tip of the anchor when there's tension on the chain
• When there's no tension, a small spring makes it swing away from the anchor, parallel to the chain

This way when the anchor is being pulled up, it'll end up getting pushed down and against the bottom's surface by that leg, preventing the anchor from being yanked out of the ground.

I can attach an illustration, but it's very basic mechanics... like a lever that pushes down on the ground to combat the upward tension of the chain. I believe it could make anchors more efficient and harder to yank out in high winds.

 

[gonzo]

Try making a free body diagram of the forces. Is is indeed very basic mechanics. The upwards pulling force from the anchor rhode can't also exert a downwards force. The downward force is a combination of gravity and of the fluke digging into the bottom. The "digging in" is the result of bottom type and the anchor type. An illustration may be helpful, but what you descrive assumes a fixed pivot point at the front of the anchor that does not exist.

 

[RainAndStorm]

I assume there will be two pivot points: the tip of the anchor and the tip of the leg, once they're both touching the ground.
The leg would convert energy of the upward pulling force into trying to "compress" the bottom, be that rocks or sand.

 

[RainAndStorm]

Heres' the basic illustration.

The point where the chain, anchor, and leg meet, it likely needs to have some sort of eccentric/asymmetric connection, that would make the pulling force turn the leg before it pulls the anchor out. This should be easy to accomplish with a little bit of design and testing. If the leg doesn't get activated or gets turned after the anchor is pulled up, then the leg will just get lifted off the bottom, but if the leg starts turning and pushing against the bottom before the anchor is yanked, means the more the chain is pulled up, the more the leg is pushed down, making it harder to pivot the anchor. If the bottom is too soft or the leg is too skinny, it'll dig into the bottom and let the anchor get removed.

It's basically gonna act like a claw when pulled.

 

[seasquirt]

Hi RainAndStorm, there should be a length of heavy chain between the anchor and the rode to weigh the anchor arm and attachment along the bottom, with only the last few feet acting as a 'spring' as waves lift and lower the hull. I vaguely remember 'the rule of 6' where 6 feet of heavy chain drags the anchor horizontally under wave strains, with the last few feet springing, and using 6 times the water depth of rode so the pull of the rope is at a shallow angle, and no where near vertical. Using that system your invention would not be needed at all, just lots of hauling up, and a decent sized chain locker to stow it all. The chain should be heavy enough and long enough to almost not even need an anchor at the end. Not so practical in a small dinghy, but even my 10 footer dinghy has a small anchor and about 10 feet of 3/8 inch chain, and it's never a problem, if the tines dig in.
Basically, the chain and anchor arm shouldn't be lifting at all.