Hi Derek,
So glad to have your friendly comment and questions. !!
Just for your information about our "Navy"(to be exact, Japan maritime self-defence force=JMSDF)
Before the end of WW2, our navy was designated as Imperial Japan Navy(IJN) under the control of the Emperor.
The Emperor's authority over the Army and Navy since the end of WW2 has been totally transferred to the prime minister and the minister of defence to control the self-defence forces. Nevertheless, the naval ensign is the common between two navies.
That being so, only "Japan navy" is recommended to use although formally to be called JMSDF.
Curious to say, I used to call normally our JMSDF "Japan Navy" whenever having talked with foreign business partners to smooth the business talks in the meetings.
Apart from the above serious matter, I reply to your questions as follows;
1)As for the thermos, hot green tea was in that since I have to drive my car for transportation of the RC boat.
Saki is not correct ,
Sake is correct to write.
2)It is still warm here reaching some times over 15 degrees C around noon and feel a bit hot in the sun with no wind really..!!
3)The bubbles were often or normally seen right after the boat passed at higher speed by which I suppose the phenomenon might have been generated by the high rotating screw props. The same kind of bubbles are also seen in my other boats frequently at hi-speed run. Not so unusual for me...
4) Sakata sea weed...??? I haven't heard about that name....
"Yamamoto" sea weed is so famous in Japan...??Kiyo