Thank you everyone for your comments.
Derek,
In the vertical position, the future deck was impacted, so I rotated it 90 degrees.It is a BIX from Forest Classics - I have used one of theirs in each of my crafts. 
The literature states that orientation is not a factor.
The tank stays in the boat.  OK, I KNOW SOME OF YOU WILL GIVE DIRE WARNINGS ABOUT EXPLOSIONS.however, even though there is a risk, once the deck and rigging is in place, I think I risk greater damage to having toput the tank in and out.  
The tank, like my boiler, came from Mike Abbott or Macsteam.  I think it is one of his last.  I have another from himin my other boat and it stays in as well.
So - in my own defense - I have procedures that mitigate the risks of gas accumulation in the hull.  
1. I fill the tank first, when I am servicing the boiler and engine.2. Then I fill the boiler, oil the engine cups, fill the lubricator, etc - all this takes 5-10 minutes.3. lastly I take a straw and blow air around the cockpit.
I still have my eyebrows  
 
 Raphael - 
I fully understand your concern.  I think it looks goofy also.BUT - I find water in the lubricator after running for 15 min.AND I find some oil in the exhaust condenser also.
I did have to open the valve about 2 full turns.  
But since the only source of oil is the lubricator, 
it seems to be working.  
Jim - 
It is CLOSED CELL.  I can see where putting a sponge up there 
would not be high on a list of good ideas.
Thanks again to all for reading.
Regards,Jim PopeDenver, COUSA