The largest production yarder that Skagit ever built was the BU-199, and Fred B. Moe logging owned 2 of these.
One was mounted on the big Skagit T-110HD Self-Propelled tower/carrier, and the other on the Skagit T-110HD Trailer.
Only 13 BU-199's were built in total. Moe used these mostly out of his operation at Clearwater on the Olympic Peninsula.