Hi Anthony,
Unfortunately there are no known photos of Boat Deck cabins on Titanic or Olympic.
The furniture plans show the Boat Deck cabins being almost half the size of an A Deck cabin to give you an idea of the spartan nature of these rooms. And there are A Deck cabin photos of Olympic I believe, so if you take into consideration how small an A Deck cabin is, and basically cut it in half, this gives you an idea of what a Boat Deck cabin would be like.
Jeremy,
>>Because of the lack of space on the Boat Deck for cabins?<<
IMO, the Boat Deck cabins were small and spartan for the penny pincher who wants to travel First Class, but does not want to shell out 200 pounds for a B or C Deck Suite - in essence the beginning of the economy class.
The only known Titanic passenger to occupy a Boat Deck cabin was Stephen W. Blackwell who paid £35 10s for cabin T on the starboard side.
Best Regards,
Brian