Propane Box


The corroded household valve in the existing propane drain. I guess this is why we use marine stuff…

When I purchased Skylark I didn’t like much about the existing propane box.  It took up a lot of room in the lazarette for the amount of propane stored,  was very awkward to access the tank which was too small for what I’m planning to do with the boat anyway.  I didn’t like the idea of storing the bottles on the rail and I didn’t want to give up any space in the lazarette.  The quarter berth on the Orion seemed too tight to be useful for anything except storage anyway so that would be the spot.

Quarter berth after removal of the existing water heater

I did my research and found some folks on the net that had rebuilt the cockpit seat into a locker by using the seat itself as the lid.  Some beautiful work but way too much effort for me.  I did’t feel that I had the skills and I didn’t want to spend the time to do a project like that.  On the other end of the spectrum I could purchase a drop in locker.  I could only find single tank lockers and wanted two 10 pound tanks so I decided to build my own by making a box with an open top and attaching it under the seat over the  quarter berth with a sturdy hatch on top and a decent drain below.  I wanted to learn how to do fiberglass work and this seemed like a great project to learn on.  And learn I did….

I decided on using two aluminum 10 pound vertical tanks and make the box large enough to also hold a gasoline container (Which is not allowed in the ABYC propane storage guidelines as the propane storage area must have no other purpose).  I calculated the minimum box height would allow for a drain that would be above the waterline unless the boat was heeled hard to port.  The drain placement isn’t ideal but seems acceptable to me.

So the major items I needed to do were build a box, cut a hole in the cockpit seat, patch the existing drain hole and mount a new above the waterline through hull.

Now sometimes I’m not such a quick learner.  I ended up with three boxes as I didn’t like the first two.  Box number one was 1/2 ply sides, 3/4 ply bottom and a huge amount of polyester resin & glass.  I could hardly lift it but I believe I could park my Toyota on it.

Take two was 1/4 ply sides, 1/2 bottom.  I switched to epoxy as i just couldn’t stand the polyester odor & vapor.  It was cold out so I couldn’t vent my work space properly and I live above that work space, yada yada ya…  By this time I had some clue how to apply the correct amount of resin and the box was OK except it took up way too much space in the quarter berth.

For box number three I dropped the gasoline storage idea and made the box as small as possible and it worked out OK.  The box was sturdy and appeared to be water proof.  Oh yikes, now I need to cut a hole in the boat.

Cockpit seat looking into the new propane box.

I had purchased a hatch that was slightly bigger than the tank diameter and I didn’t want to need to fix a big mistake here so I carefully measured & remeasured and measured some more.  I finally drilled a pilot hole to measure off of again.  You can see in the photo above I laid  it out wrong at first.  I was really lucky because when I drew the incorrect layout lines, I took a deep breath, picked up the circular saw, bent over to start the cut…and ran out of gas in the generator.  Did you ever have an experience like that?

I attached the box to the underside of the seat with stainless screws and sealed the joint with butyl tape.  I had attached 2 cleats on the inboard side to rest on cleats attached to the vertical part of the cockpit well.  I then built up pylons on the outboard side from thickened epoxy and ply spacers to match the curve of the hull.

Here the box is installed and I’m starting to trial fit the water heater.