Dearman,
I have a 15ish foot inflatible with 35 horse engine. I recently sold he engine (I am getting a new one at some point) but I am keeping the boat because we bought a BW sometime back. Yes, I have dived solo off both in lakes and in the ocean. Thing is my wife is usually on anchor watch. I also dive solo off of my Ocean Kayak Scupper Pro TW. I paddled it all the way out to the first Libety Ship reef at Destin and Amberjack.
Yes, on the BW my wife stays aboard--so far---on the kayak and the inflatibe I just kept myself tethered most times unless it was shallow and no current. I dived a number of areas in Florida east coast solo with the inflatible, great for drift diving because it just comes along with me. N
I would not recommend tech type diving solo since I assume that type diving imples decompression diving with all the bottles they haul around.