Thursday, June 27, 2013

Stove gimbal pivots

Another little project post.

I have a Force 10 stove.  As the boat is constantly rocking while at anchor or underway, the stove rotates on two metal pivots which attach to the stove and fit into two brackets:

This is all very standard - stoves on boats gimbal in order that they mainly stay horizontal as the boat moves around them.  When I had my stove out last autumn after returning from my journey I was surprised at the state of the pivots.  Here they are:

I bought this stove in 2009, so its not very old.  I used to notice what I thought was dirt beside the stove, you can see some of it in the photo of the space the stove fits into above.  I now believe the 'dirt' is mostly metal fragments from the pivots being eaten away.  The pivot on the left in the photo above looks like its eaten roughly 1/2 way through.  The one on the right looks like its further than that.

In quiet waters, the stove doesn't rock back and forth very much.  On a passage or in a rougher anchorage or mooring the boat rocks constantly which means the stove is constantly rocking back on forth on these pivots.  You end up with a metal on metal chafe, and over time the pivots would be eaten completely through.

Before last autumn, this wasn't something I could inspect very easily - getting the stove out meant I would need to disassemble the grab bar and go through contortions to get the stove out.  Last fall I modified the fiddles above the stove slightly and getting the stove out now is relatively easy.

I recently replaced the two pivots with two new ones I had ordered.  Also note that the pivot on the left has two grooves.  I noticed this as if the stove was resting in one of the grooves the stove would swing freely in its space, while the other groove would mean the stove would hit parts of the frame around it when it swung.  This was annoying.  I added some nylon washers to the pivot on the left in order that the stove always remain oriented properly - swinging freely.  Before leaving I had noticed that the stove needed a little nudge into the proper spot in order to swing freely, but didn't think much about it.  I know better now...

Nylon washers around the forward pivot to properly position the stove in its space
I'm also going to add a maintenance item to lubricate the gimbals from time to time.  I'll try just dripping some oil down onto the gimbal from above.  I hope that works.  The point being that the pivots need to be lubricated.  I didn't know that.

I'm now carrying an extra set of the pivots for a future replacement, but hope to never need them.

If any of you have boats with stoves which gimbal - you might want to look into this.  If your stove enclosure has grey or dark 'dirt' along its sides, below the pivots which you don't think is simply food related - your pivots may be wearing!  This is likely not a problem when sailing in local sheltered waters.  But offshore the waters aren't always so sheltered.

I've been following the travels of Jeanne Socrates on s/v Nereida as she completes her single handed, round the world, non-stop, below the 5 southern capes trip.  Back in May her stove broke off its gimbals.  I wonder if her problem was related to what was happening to mine?

Update: July 1st.

It was pointed out to me that I should be locking the stove into the frame to keep it from swinging when its not in use.  This wasn't something that occurred to me a single time while I was out cruising last year.  I wonder how many people do that?

I found this on page 10 of the Force 10 manual:
The bolt should be locked into the adjoining cabinet or bulkhead whenever the range is not in use to prevent it from swinging in rough seas.  ...
The manual didn't mention: "or else the stove gimbal pivots will wear through and the stove will fall off its mount!"  A little drama helps these types of warnings...

I always had my kettle stowed on the stove when the stove wasn't in use.  There were seas I was in where the kettle would have launched itself off of the stove if it was locked and not able to gimbal.  But that's a better problem to solve than having the mounting pivots eat through and having the stove fall off its mount.

So that's good advice.  I should be locking the stove against swinging when not in use.  Something to consider for you others...

1 comment:

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