Well, as with many things, it depends! If she has an engine, then she needs the lights that any motorized boat needs – red/green for port/starboard illumination and, for convenience, an all-around light that functions as both a stern and mast light. Being that you note that she is an inflatable, I wonder about the battery configuration to supply that energy – which also needs to be tied into your engine for ongoing recharging.
If she’s a sailboat, without an engine aboard, then Rule 25(d)(i) controls. Unless she has neither sails nor an engine, i.e., you’re rowing, in which case Rule 25(d)(ii) controls.
Rule 25 – Sailing Vessels Underway and Vessels Under Oars
(a) A sailing vessel underway shall exhibit: 
(i) sidelights;
(ii) a sternlight.
(b) In a sailing vessel of less than 20 meters in length the lights prescribed in Rule 25(a) may be combined in one lantern carried at or near the top of the mast where it can best be seen.
(c) A sailing vessel underway may, in addition to the lights prescribed in Rule 25(a), exhibit at or near the top of the mast, where they can best be seen, two all-round lights in a vertical line, the upper being red and the lower green, but these lights shall not be exhibited in conjunction with the combined lantern permitted by Rule 25(b).
(d)(i) A sailing vessel of less than 7 meter in length shall, if practicable, exhibit the lights prescribed in Rule 25(a) or (b), but if she does not, she shall ‹‹ exhibit an all around white light or ›› have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision.
(ii) A vessel under oars may exhibit the lights prescribed in this rule for sailing vessels, but if she does not, she shall ‹‹ exhibit an all around white light or ›› have ready at hand an electric torch or lighted lantern showing a white light which shall be exhibited in sufficient time to prevent collision.
For your convenience, I’ve included Rule 20 which states when these lights “shall” (which means “must”) be used. Only when the Rules say “may” do you have any flexibility.
PART C – LIGHTS AND SHAPES
Rule 20 – Application 
(a) Rules 20-31 shall be complied with in all weathers.
(b) The Rules concerning lights shall be complied with from sunset to sunrise, and during such times no other lights shall be exhibited, except such lights which cannot be mistaken for the lights specified in these Rules or do not impair their visibility or distinctive character, or interfere with the keeping of a proper look-out.
(c) The lights prescribed by these Rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility and may be exhibited in all other circumstances when it is deemed necessary.
I’ve included Rule 20 because, if you never get underway from sunrise to sunset or in restricted visibility, you’re not in violation of Rule 20, which triggers all the other light Rules. However, a perfectly nice day can devolve into rain and/or fog pretty quickly – and then you’re in trouble both from a legal standpoint and from a safety of life at sea standpoint!
Be safe out there!
Commodore Vin Pica
BTW, if you are interested in being part of USCG Forces, email me at JoinUSCGAux@aol.com or go direct to the D1SR Human Resources department, who are in charge of new members matters, at DSO-HR and we will help you “get in this thing…”
We’d appreciate it!
