This evening I realized that on the "internet", people use "email" and have "websites". So I did some googling, and there was a website for Mike Pinera - guitarist/vocalist for The Blues Image, and co-writer of this song. I sent an email asking about the identity of the instrument and got a quick response:
The instument that your asking about was a special organ, I believe was called a Gulbranson. The intro we tried to make it sound like a ship's horn and on the counter melodies we went for a flute/recorder sound.Gulbransen made some spinets in the 50s and 60s, including the first transistorized tone generator organ (Model B). The discussion will probably turn now to figuring out exactly which model they used, and what settings/voices they used for the track. At some point I'll probably take on the irrational but inevitable quest of tracking one down for the collection.
Speaking of, "Ride Captain Ride" probably has one of the wider ranges of interpretations I've read about (everything from Scientology boat trips to the attack of the USS Pueblo). Here is an interesting anecdote that should clear that up as well:
"The producer came in and said, "Do you have any more songs, because if you don't, this is your last day in the studio,"' Pinera says. "So I said, "Oh, I have a song,' which I didn't. So I went into the bathroom, and I shut the door, and I just meditated. I calmed my mind, and I started hearing music. I went out and sat at the piano, which was a Rhodes Model No. 73, which had 73 keys. So I say, "Okay, I need a first word.' And what came into my head was 73. I liked the rhythm, and I went, "73 men sailed in, from the San Francisco Bay. ... The song sort of just wrote itself."