I was thinking the same thing, but it seems tad smallish for that, at least by modern standards. I would guess it was used as a captain's GIG, but in WWII, whoh knows possibly an admiral's BARGE.
We carried one similar craft on each of the three guided missile destroyers I was assigned to back in the 70s and 80s as a captain's gig. We also had a 26-foot whaleboat. One the larger DDG, we also had a 36-foot open personnel boat.
The only time I ever rode in the gig was when the captain invited me. Otherwise it was usually in the hired shore boat which could carry many more of our crew than the small boats we carried.