Successful build - Chance fights ever on the side of the prudent.

Link to build: https://jenkins.wildfiregames.com/job/differential/1253/display/redirect

You're correct, currently the generic fishing boat template does not specify a status bar, which means it defaults to the values of the template_unit.xml file. If desired, I suppose I could insert those into the fishing boat to preserve its status bar size.
However, is it really important that the fishing boat has a status bar different from all other ships? Does it convey some information to the player that will be lost if it's standardized?
For comparison, without this patch:

I guess the barsize is related to the size of the visual actor, and the big one might or might not look uglier. (Perhaps it becomes more clear if there are more ships or more units in general, but probably it's not so bad)

Well that tells us that fishing ships are intended to have a regular sized status bar, not the larger one from bigger ships. I would say make a copy of template_unit's status bars for that template and keep your change otherwise.

Personally though I'm also fine with giving the fishing ships a large bar similar to other sips.

Imho the large bar looks to big for the small fishing boat

*@Stan wishes health would be displayed in the footprint instead.

I agree with @Imarok that the health bar looks too big for the little fishing ship. How does it look from afar ?

Successful build - Chance fights ever on the side of the prudent.

Link to build: https://jenkins.wildfiregames.com/job/differential/1293/display/redirect

More ships and from afar, current smaller status bar:

Ugly water is really ugly ^^"

Yeah, small is better, it gets confusing otherwise.