My guess is that you are talking about the boat loader and not the roof racks?http://www.yakima.com
Go to the link I showed you and look at the guy hanging on the boat loader. He looks like he weighs more than 60 pounds to me. Remember, you are not transporting the yak on them, just temporarily supporting the yak until it is moved onto the roof racks.
If you were talking about weight capacity of the roof racks themselves I believe they are all designed to support 165 pounds but the set up for you individual vehicle may reduce that. I have a Hyundai Elantra (small vehicle) and the same roof racks when installed on my vehicle has a weight limit of 125 pounds. With the seat and mirage drive removed from a Pro Angler 12 it is within the capacity of the racks.
I hope that helps.