Chameleon Tug

Back in September I caught this tug on its way to the races. I wondered where it lived.

 

Finally I put it together with this shot I took last February, although back then it had no orange band on forestarboard bulwark.

Same vessel, though. Anyone know the name/function of the structure extending upward from the stem?

 

Long Splice, what it sounds like here.

Photos, WVD.