Boat Battery Dispenser

I previously made a battery dispenser for the house (you can buy a commercial holder, but I wanted a dispenser). This first model was a trial and error wood design and had to be mounted a couple inches from the wall.

I used  #4 machine screws and ballpoint pen springs as 'plungers'.

It works well, but I wanted a flush mount for the boat and if I could make it lighter and moisture-proof that would be nice too, so I bought some Expanded PVC sheets - 1/8" and 1/2" to experiment with.

I love this stuff - it's a great boat material - easy to cut and shape. It's waterproof and unlike Starboard it can be easily glued to not only itself, but to wood. I did some tests and was impressed with, Gorilla Glue, All Purpose Cement (Oatey 30821) and epoxy. Silicone worked, but as to be expected, I wasn't impressed with the holding.

The 5200 takes so long to cure I gave up on it.

So onward and upward with the Expanded PVC. The first challenge was how to flush mount the unit and still get the batteries out. I came up with a 'puller', made from a brazing rod. This required a hole for the rod, a slot to allow it to be pulled out and a recess in the backing plate to keep the 'puller' out of the way unless it was being used.

This was a test model to see how things might go and what sizes would work.

I liked the 'puller' despite not having a firm solution as to the vulnerability of the exposed ends of the pull rods.


With the wood version, I cut relief slots in the backing plate to slide the dividers into for gluing. I also made spacers to keep the dividers vertical while the epoxy set up. This time I would use the spacers with All Purpose Cement and stick the dividers directly to the surface of the Expanded PVC back plate.

The wood spacers were cut away at the lower edges to keep oozing glue from sticking to the spacers.

I glued  four vertical guides to the backing plate so it would be easy to position the divider group on the plate after glue was applied to the 1/8" divider edges using a syringe.

I was happy with the results the next day after the glue has set up.

I mechanically fastened the 'puller' base and the sides (w/ stainless sheet metal screws) so if things didn't work out I wouldn't have to un-glue anything, but so far except for the slightly larger areas between the dividers, everything is working better than expected.

The little handle at the top of the unit allows the plexiglass front to be raised to 'refill' the dispenser.

On the wood version, I shimmed out from the base so each column of batteries would be close to the plexiglass. On this version I'll see if that is necessary before going to the trouble.

And unlike the home version where any battery can always be dispensed, the marine version will have a lower plexiglass position that will keep the batteries captive while the trailered boat is being jostled on the road or in enthusiastic sea conditions.

I still haven't decided what to do with the exposed rods...maybe a small knob on each or I could bend them down 90°? We'll see.

~Addendum~ 

Over 20" of "D" cells falling after one is removed is quite a strain on the dispenser. Also, I realized that on the boat I don't have the luxury of a lot of room to slide the plexiglass up to refill the dispenser. Even after cutting the boat unit down to about 11" I still didn't have room anywhere on the boat to slide up the plexiglass to reload the dispenser. 

I bent the pull rods down 90° to see if I could slide the plexiglass down past them, but there wasn't quite enough clearance. I though about relieving the base so I could make new rods and bend them sooner for clearance. This would mean a complete rework of the base and new pull rods so I got to thinking about something kinder if a battery was needed on a rocking boat. Maybe pull tabs of some kind? 

I found an old USPS Tyvek envelope and cut it into strips the width of each battery column, then glued them to the backing plate about half way up letting them hang out the bottom by about an inch. This worked well enough that it was worth mounting on the boat.

My 40 year old houseboat get's a couple mordern touches.

The double stop sliding plexi front is held in place by the removable stop about 1/2 way up on the right side. And now I can be comfortable knowing even though I don't keep batteries in my non-pyro emergency device, that I have them visible and conveniently on hand.

Aquamatic Propellers - Fitting a Long Hub Propeller to A Short Hub Shaft

I go through Aquamatic props regularly. We like to explore remote areas that are often quite shallow. My 250 outdrive takes the short hub propeller – the one where the bendy tab locks the cone.

The place that I’d been getting the short hub props no longer handles them. I bought a long hub prop – the one that uses a bolt into the end of the cone to lock it, just to see if I could make it work. I couldn’t come up with a solution. That long hub propeller needs a threaded shaft and mine isn’t threaded.

My 250 drive requires the #5 bendy tab to lock the cone.

I’d heard you can thread the shaft, but it was a scary thought. Is it hardened? Does it take a special bit and tap? How do you know if you’re drilling straight? Then one day I chucked up a 17/64” Harbor Freight bit just to see if I could put a hole in the end of the shaft, and what do you know, it wasn’t difficult to start the hole.

OK, so I could drill the hole, but how do I make it straight? I’d need a guide of some kind. I was excited to find that he (external) cone threads on the shaft are American 5/8” X 11.

Damn - these are SAE Threads.

There’s a threaded rod coupler 5/8 X 11 that will screw onto the cone threads on the propeller shaft. This was a start. Now all I needed to do was figure a way to keep the drill bit centered while I was making the hole in the shaft. 

I thought I could find a sleeve that I could use inside the coupler but nothing I found would fit snugly.

I found that a 5/16 nut could be pushed into the end of the coupler. This would not be a real snug fit, but it would keep the drill bit centered in the outward end of the coupler. There is already a dimple in the propeller shaft so the other end of the bit would start correctly.

I drilled a 17/64” hole about ¾” into the propeller shaft and used a reputable 5/16 X 18 end tap to make threads a little over ½” deep.

You may need to 'clearance' the nut to get a good fit for the drill bit.

I’ve seen all kinds of spacers on both sides of the propeller so the only way to know how long the locking bolt should be was to fix the propeller and cone on the propeller shaft and push the locking bolt in until it contacted the shaft. I’d want to have just a smidgen of shoulder above the top of the cone – this would give me more than ¼” of threads to grab but wouldn’t bottom out.

If the bolt is this long before you start screwing it in, you'll grab ~3/8" of the new threads.

 Now, after all was said and done, I remembered that I could have just used the lathe to poke a hole in a 5/8" bolt to use in the end of the coupler.

At any rate, I'm no longer being held hostage to short hub propellers. Now I can use both.

Battery Dispenser

A while back I mentioned using a syringe to place glue. The intent was to make a battery dispenser - I knew there were already battery holders available - I even bought one. But I thought I could do better. This is how it started out...by gluing plywood guides spaced to accommodate different sized batteries - D, C, 9, AA and AAA sizes.


 I got to thinking that this approach was a little clunky, so I regrouped using doorskin dividers and I'm happy with the results.


If you look closely you can see a lexan sheet that slides down over the batteries. I'd originally thought a hinged cover would be the way to go but after working it up decided to do it this way.




Now, how to 'dispense' them? Pull them out with a magnet? Make a fabric strap for each compartment so I could pull them out? Some kind of lever? I decided on a plunger.

These are 2" #4 machine screws using ball point pen springs (8 pens for $1 @ Walmart) with countersunk nuts on the battery ends to keep them in place.

Now all I have to do is reach under the proper battery and push the plunger to get the one I want.



Not to mention that it's easy to keep track of the inventory.

The unit does stick out from the mounting place, but with proper consideration, that's not a problem.


So, we have proof of concept, but it works so well I'll just use it the way it is.