as far as i know, any newer 27' 5th wheel will have an ultralight frame, which attempting to tow a boat with, will void the frame's warranty and possibly the trailer's warranty if any flexing causes issues with the walls/roof.
maybe an older 27' 5th wheel might not be an ultralight but without knowing the year/make/model, can't say for sure.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC