William Henning sure drew ugly. He animated some of the most unappealing and crude looking Popeye I've ever seen. But that said, this is an equal opportunity blog, so all Popeye animator styles that can be identified will be represented here.
Probably the second most prolific Popeye animator next to George Germanetti, Henning's work spanned 3 different periods of the character and can be found in Fleischer, Famous Studio and King Feature Popeye cartoons.
Part of the old guard at the Fleischer Studio, Henning was a senior member of the staff for approximately 7 years by the time Popeye started into production - 1 year longer than head animators Seymour Knietel and Willard Bowsky. Before becoming an animator in 1931, he was head of the inbetweening department.
A member of Seymour Knietel's unit for years, Henning animated on Popeye from 1933 until 1939, when at that time, he was briefly given the job of head animator (de facto director) on a couple of Popeye cartoons. His early Famous Studio years had him working for a short time in Jim Tyer's unit and later with Tom Johnson's unit. In between he did brief stints with Nick Tafuri and Bill Tytla. (whom I believe exercised more directorial control over his pictures than did Knietel and Sparber)
Henning was considered good at drawing and animating 4 legged animals and often given scenes of that kind according to animator John Gentilella.
Once Henning established his animation and drawing style it evolved marginally as compared with the advancement of his peers. Coming into the Famous Studio years, his style looks frozen in time - much of his later work looking like it still belonged in the Fleischer cartoons.
A gossip piece in an issue of the Fleischer Studio's news publication stated that Henning was decorated for his service as a captain in the German army prior to working in animation. I wonder if that sort of regimented military attitude affected his animation.

Seasin's Greetinks - 1933
Check out Michael Sporn's analysis of this animation at his splog (Oct.30 post):
http://www.michaelspornanimation.com/splog/index.php?paged=2

Strong to the Finich - 1934

A Dream Waking - 1934

The Spinach Overature - 1935

Vim, Vigor and Vitaliky - 1936

Bridge Ahoy - 1936

Lost and Foundry - 1937

Protek the Weakerist - 1937

Cops is Always Right - 1938

Ghosks is the Bunk - 1939

Wood Peckin' - 1943

We're on Our Way to Rio - 1944

Puppet Love - 1944

Service with a Guile - 1946

Wotta Knight - 1947

Robin Hood-Winked - 1948

Quick on the Vigor - 1950

Big Bad Sindbad - 1952

Cookin' with Gags - 1954

Gopher Spinach - 1954

Out to Punch - 1956

Butler Up - 1961
Here are 2 examples of Henning's Popeye - 10 years apart with basically the same drawing style and expression:

Strong to the Finich - 1934

Puppet Love - 1944
Next Animator ID - Charles Hastings (the 'off model' Popeye animator)