Rocket Boiler

I need is a plan Rocket mass heater that heats water, (yea, probably unpressurized as we don't want to to "Boom Squish" I would probably do a batch rocket heater ask I would not want to constantly feel the heater as I believe you have to do with the J tube heaters.  What I would want to do is heat the water for the day or two usage  when the weather is mild and more often when it gets colder. Have we had anyone work something since the Rocket Mass Heater DVD sets? (I have watched 1 and 2) I think I want to make an outside ( Small  outside shed one) to avoid increased insurance costs.
 Any help would be appreciated.

Eric -

Have you seen the Richard Hill Stickwood boiler?  This was from the bad old days of the oil crunch.

He was a professor at University of Maine, and developed a wood fired atmospheric boiler under a US Department of Energy grant.  It was quite similar to a J-tube, but used both forced and induced draft.  The best quality scan of his DOE report that I have found is here:
https://web.archive.org/web/20260122141201/http://www.hotandcold.tv/resources/woodfiredfurnace.pdf

He does give some details of the water tube boiler.  He batch fired the burner, stored the heat in two used fuel oil tanks, then pumped the hot water through his heating loop for a couple of days before firing again.  He had a small expansion tank in the attic, open to atmosphere.  This might give you a starting point for the boiler side, but using a J-tube as the burner.

I am currently investigating whether adding a home brew biomass burner - either pellets or cord wood - to a low pressure steam heating system (under 2psi, and with the new Vaporstat, maybe under 10 oz/in2) is possible - or wise.  I know I could do it by converting to a vapor system, but I am trying to come up with something that is a longer term off-grid solution.  I the power is out for a week because there is a big ice storm or the local substation in non-operative due to a mishap, I'd rather be the one with the house where all of the pensioner neighbors can keep warm than the one who is freezing right along with them.

I may end up just running a parallel heating system - RMH, or similar.