I and a couple of friends were planning a float down the Ivishak for grayling and dolly fishing along with peace and solitude this September. After a bit of review, we thought that we could get a 'bou tag and if they happened to be around, hunt them as well. I found this forum, which is a wealth of info (thanks to all of you who participate). Then I started to see the number of archived posts about boat access with anything from jets to go-devils to airboats to the Ivishak via the Sag.
My question is: how many and how far up the Ivishak do the boats typically go and how many parties float the river in early September? Some of the forums posts seem to indicate that the number of people motoring up the Ivishak and others floating down in early September would make this into a combat float, which is not exactly what I was aiming for in a north slope float.
You answered your own question. I would expect to see at least five or 6 groups above the boat limit after that much more if the Bou are there fewer if the Bou aren't there.
Plus quite a few guys get flown in and float the Ivishak to the Sag for Bou and pull out at the road. You could be alone or have lots of company it just depends on timing!