I use two types of canister fuel on the boat, 1lb propane for the grill, and small butane for the galley stove.
I made two PVC storage "lockers" for two each of the canisters. They live attached to the sidewall of the starboard-aft cockpit seat. Each of the caps have a line attached to keep them from getting dropped overboard:

The standard PVC tubes (forgot which dimensions) fit exactly the propane and the butane diameters, one large, and one small. At the bottom of each, I glued a standard PVC "shower drain" for venting and water drainage.

Here is the propane one. I bought two of those brass reusable screw-on lids on ebay - they are really nice. They still need anti-seize or lubricant to keep them from rusting on.

.....and the butane:

Each of the lid bottoms has a line with a "choke collar" that goes around the neck of the bottom of the two canisters to allow you to pull them up from the tube.

The PVC is screwed into the bulkhead, through a piece of black starboard to raise the lids away from the side. The flathead screws are countersunk (as much as you can in the side of PVC) on the inside to protect the canister. Larger holes are opposite the screw locations on the outside of the PVC for access.
All pics and text also in the album.
Ray
I made two PVC storage "lockers" for two each of the canisters. They live attached to the sidewall of the starboard-aft cockpit seat. Each of the caps have a line attached to keep them from getting dropped overboard:

The standard PVC tubes (forgot which dimensions) fit exactly the propane and the butane diameters, one large, and one small. At the bottom of each, I glued a standard PVC "shower drain" for venting and water drainage.

Here is the propane one. I bought two of those brass reusable screw-on lids on ebay - they are really nice. They still need anti-seize or lubricant to keep them from rusting on.

.....and the butane:

Each of the lid bottoms has a line with a "choke collar" that goes around the neck of the bottom of the two canisters to allow you to pull them up from the tube.

The PVC is screwed into the bulkhead, through a piece of black starboard to raise the lids away from the side. The flathead screws are countersunk (as much as you can in the side of PVC) on the inside to protect the canister. Larger holes are opposite the screw locations on the outside of the PVC for access.
All pics and text also in the album.
Ray