Thanks everyone for the comments and thoughts.
I use a fat, sit on top kayak called a NuCanoe. It is quite broad beamed, so not too tippy. I have a boat seat that has been modified to sit in the base of the kayak, with a pedestal mount to support the Wimberely head. This is the first time I shot with the 500 on it, and it went well. I only am out in very calm conditions, so don't have to put up with the wind.
In order to free my hands to photograph, I have a remote controlled trolling motor mounted on the bow.
I don't have any pictures of the kayak, but will be back on the lake in a couple of weeks, and will try to take a picture of my rig and post it here.
Jakov: re; blown highlights. The breast was at 252 in several places. I normally like around 235 or so, so will revisit the raw and see if it can be massaged a bit.
The loons on this lake are used to people, and generally tolerant. My friend puts out the artificial nesting platform that they use, and spends a lot of time with them in his kayak, so they are used to that type of visitor. Because I have a cottage on that lake, I can spend a lot of time just sitting in the water near them, letting them learn that I am no threat.
After a while, they often just ignore me.
because the same pair of loons will stay on one lake for many years, they do seem to develop a memory of people or boats that have been around them a lot, and are very tolerant of that person.
It is person/boat specific however. I have a different lake I go to, and have spent a lot of time with them. When my friend takes his kayak there, they will have nothing to do with him, and just swim away. On the lake where my cottage is, my friend has spent more time with them than I, and they let him drift within feet of them, but until just this year, they wouldn't tolerate me in my dull brown kayak! I thought of borrowing his blue kayak to see if it was the color!
Fascinating to watch them. They are spectacular parents.
They usually lay two eggs only, and sometimes only one will hatch, so the family is always small.
Randy