How do I determine what weight of a second anchor to hold the boat in place?

[soccs11]

Going to the sand bar on Lake Wylie in SC and I see that most boaters there have a second anchor out to hold their boat in place. Right now I only have one anchor; so I need to stay away from the other boats because my boat will move while their boats stay in one place. How do I determine what size anchor and what style anchor to use for my second anchor? Thanks. I have an 18 foot pontoon boat.

[riplipper]

Your second anchor can be very small and light if you use it on the front for the sandbar. No chain needed.
Some people even use stick pins for that application.

[Steiner]

First option: Save the money and ask someone if you can tie off to them.

Second option: If close to shore, large size stake anchor. I've tried the smaller one and it does not hold well with a few waves.
https://www.amazon.com/Extreme-Max-3006 ... r=8-9&th=1

Third option: Baby box anchor. No chain and 2:1 rope scope. Actually if you are only on lakes the box anchor is what you want for your main anchor too if you don't have one. The "small" is 19lbs, the "baby" is 13lbs. I have two smalls and one baby and only use the baby and have a very heavy tritoon.
https://www.amazon.com/Extreme-Max-3006 ... =8-10&th=1

I lost a small one in 20' of water one year. Had a guy that does scuba for donations burn up two tanks looking for it and couldn't find it. Bought a magnet fishing kit and wore myself out trying to find it. A year later, I threw out anchor in the same spot and hooked the lost one. That's why I have two smalls. Went out and bought forty lottery tickets that night. I won $12.

[soccs11]

Thank you all for the information. Cheers.

[Steiner]

Box anchor video
https://youtu.be/Mv2ybwgcaL8?si=J4uaCE0wJYj9JXI5

[MattGent]

The little baby Mantus dinghy anchor is fantastic in sand. Small, and comes apart into flat sections for storage if you need to.

I use it as a main anchor on my 16' toon and as a second on my 25' pilothouse.