“Barnacles” sounds like “bar nickels,” and, of course, there are jokes. A pirate riddle was posted on Twitter by Laguna Playhouse on April 18, 2011:
   
Q: How do pirates pay for a round o’ rum down at the pub?
A: With Bar-Nickels!
   
   
Wikipedia: Barnacle
A barnacle is a type of arthropod constituting the infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile (nonmobile) suspension feeders, and have four nektonic (active swimming) larval stages. Around 1,000 barnacle species are currently known.[1] The name “Cirripedia” is Greek, meaning “curl-footed”. The study of barnacles is called cirripedology.
 
Twitter
Laguna Playhouse
@Lagunaplayhouse
Q: How do pirates pay for a round o’ rum down at the pub? A: With Bar-Nickels! More pirate fun at TREASURE ISLAND http://ow.ly/4CJT1
2:09 PM · Apr 18, 2011·Hootsuite
 
Twittr
Glyn Le Var
@boylevar
How do pirates pay for rum at the pub: with bar-nickels.
How do pirates know there pirates: they think therefore they arrr..
3:37 AM · May 7, 2011·Twitter for iPhone
 
Twitter
Tania Hussain
@westlifebunny
@PantherElectric
Hey Bob! How do pirates pay for a round of rum down at the pub?...with BAR-NICKELS! See? I didn’t ARGH you in that one! 😊
7:31 PM · Jun 28, 2011·Twitter Web Client
           
Chile Underground 
Today is National “Talk Like a Pirate” Day; Prepare to Be Boarded…
By Chile Doctor, on Monday, September 19th, 2011, at 8:00 am
(...)
Q: How does a True Pirate pay for his rum at the bar?
A: With bar-nickels.
 
The Pirate Empire
Monday, April 21, 2014
16 Terrible Pirate Jokes
Arrr these the BEST pirate jokes? Or the worst?
(...)
Q: How do pirates pay for a round o’ rum down at the pub?
A: With Bar-Nickels!
   
Alex Bledsoe, author
Leah
09.18.2014 AT 7:57 PM
On facebook you used to be able to choose “Pirate” as your language. I had it set to that for a while but I couldn’t understand the language well enough so I had to switch back to English.
 
Here is my joke: How do pirates pay for a round o’ rum down at the pub?
 
With Bar-nickels.
 
Les Listes
Top 101 Best Pirate Jokes
Posted on December 6, 2018
(...)
7. Q: How do pirates pay for a round o’ rum down at the pub? A: With Bar-Nickels!
 
Reddit—Alcohol
Posted by u/johnfoster8 September 27, 2019
How do pirates pay for a round o’ rum down at the pub? With Bar-Nickels!
 
Twitter
Science Uncorked
@ScienceUncorked
“How do marine invertebrates pay for #wine?
They use bar-nickels!”
(get it? ... barnacles ... 🤗)
@ben_rubinoff kicks off #ScienceUncorked w/ a laugh for a packed crowd @gourmetaubay!
#scicomm #sciencejokes
9:13 PM · Nov 13, 2019·Twitter for iPhone