Funny Little Homemade Anodes

[resilientg]

Hi there,

I have these funny little anodes on my 28' steel boat. (see pic)

I have some of them already installed by the deceased previous owner, but i will need to add a couple more.

My understanding is that they should have a coverage of 3 meters radius, is that correct?

Also this particular boat had a lot of love put into by the previous owner so im assuming that he thought about these anodes as they appear to all be hand made and that the size for the anode is correct, what do you guys think.

Current placements are

two on the port side amidships near the engine intake about 400mm apart.
one on the starboard amidships side near the transducer pod
one on the rear port quarter behind the sum log

the places that i was going to put the other three were

two forwards, one each side of the hull and one aft opposite the one behind the sum log

i will also put an anode on each side of my rudder.

Oh yes and there's a normal shaft anode on the shat too?

So is the size of these little guys adequate?
Is my planned placement seem OK?

should the anodes be re sized in any way?

ideally i would like to use these anodes if possible untill they die then change them to something that is a current shape and readily available.

Thanks in advance

Matthew