What type and weight anchor should I get for a 13' raft?

[mark m]

Hi,
I'm looking for an anchor for my 13' Hyside self-bailing raft for rivers. Should I get a pyramid type anchor or an anchor with small spikes? What weight should I get? Lets say getting an anchor with flows on the American River about 6000cfs.

Thanks
Mark

[Bill Kiene semi-retired]

I am going to guess a 20# pyramid lead anchor.