I've been able to carry the bar & lines on in the past, but it wasn't allowed on a flight about 18 months ago from Ireland to USA and I'm lucky the security employee was kind enough to walk me to special baggage and he had it bagged for me as extra luggage with no charge...but it could have been another not so pleasant person and that would have meant "lose the bar or miss the flight". I'm not sure I would risk it again. Fins might be a problem too. Forfeiting wither of these things would be a costly and inconvenient disaster.
Enforcement and policies seem to be so capricious from one employee to another. I'd play it safe though. You can't argue with these guys very successfully and the minute you start they seem to become even more unreasonable...and you can be denied boarding if you complain too much.
on a related note - I saw a "jacket" someone invented that is basically a suitcase you wear as a vest...you can pack quite a few things into this "jacket" and they have tested it with al the airlines. Basically give you the volume of an extra "carry-on" bag. Looks pretty goofy but then the baggage limitations are goofy too.http://www.rufusroo.com/shop/