Freeze Free: Easy Lock Maintenance

Maintaining locks in paradise can be more important than you think!  The first year we were commuter cruising in the Western Caribbean, we left the boat with the outboard locked to the rail, the same as we had done for years prior in the USA.  Corrosion is a bigger factor the farther south you get in more extreme conditions.  Except we didn’t know that … yet.  Returning to the boat, we unlocked the outboard to put it on the dinghy … except it didn’t unlock.  It was stuck solid.  Over the next three days, we tried soaking it in PB Blaster, WD40, TD9 Boeshield and every other lubricating/corrosion busting spray anyone recommended!  It got to be the subject of happy hour … “how’s the lock”?  Our caretaker suggested that he’d only seen one outboard with this type lock stolen in the Rio Dulce and that maybe we should find the guy and offer to pay him to steal our outboard off the rail!  Finally after days of corrosion busting stuff and many different highly engineered leverage schemes, the lock magically gave up and we had our outboard back.  Then we went through the same process with our kayaks which were locked to palm trees close to the dock.

Needless to say, ever since then, we’ve been more vigilant with our locks!  This article was published in SAIL Magazine, August 2010, On Deck/Cruising Tips section.


Like everything on a boat, locks require maintenance … or you may find your outboard so securely locked to the rail that it requires a Dremel to cut the lock!   Here are some tips – they may not be perfect, but this routine has kept our locks unfrozen for the past 5 years.

  1. Every six months, soak each lock in plain white vinegar to dissolve corrosion or salt buildup – depending on how serious the corrosion or rust, you may need to soak them for an hour or longer.  The first time we tried this, we had to soak them all day!   Make sure the vinegar covers the locks and turn them from time to time.
  2. While still in the vinegar, use a wire brush, remove any visible corrosion.  Don’t forget to open the lock to reach corrosion hiding inside.
  3. Let dry in the sun open for several hours, until inside and outside is dry.
  4. Using a good corrosion inhibiting lubricant, lubricate the locks according to the manufacturer instructions.    Since I lost the instructions years ago, I just spray lubricant into every hole in the lock.   Be sure to do this over a paper towel since excess that runs out may be very rusty.     Wipe off excess with a paper towel.
  5. After trying several lubricants, our recommendation is Tri-Flow Superior Lubricant.   According to the spray can … it penetrates quickly, loosens rusty parts, frees sticky mechanisms and washes away dirt, corrosion and contaminates.    Then it “protects with unique premium formulation inhibiting rust and corrosion, displacing dirt, grit and moisture and withstands temperature extremes, salt spray and high humidity” …   our experience is that this is one product that lives up to the claims.    Tri-Flow comes in a black spray can, is manufactured by Sherwin Williams and can be difficult to find.  We usually find ours in a local Ace Hardware and you can also get it online at Amazon — if you click this link, makes a few cents to help support the site.

    Tri-Flow Lubricant

    Tri-Flow Lubricant

  6. Work each lock several times, resoaking and relubricating if necessary until it works smoothly.
  7. Add lock maintenance to your monthly maintenance routine.   On the first day of each month, just as surely as we check the water in our batteries, we relubricate each lock.    So far, knock on wood, we have had no more frozen locks from leaving our boat for six months at a time in paradise!

For more on maintenance, you may want to read 10 Tools You Never Knew You Needed!

If you have lock maintenance tips that have worked for you, share them!  Leave a comment below!  THANKS!



  1. Great advice …. thanks for the info!

  2. Lock maintenance is necessary in the high latitudes to “help” prevent low temperature freezups not to mention the effects of corrosion so here is what I recommend.

    The Vinegar soak is good to help free neglected locks, but better to not neglect them in the first place, so here is what works for me.

    With a new lock, or the above Vinegar reconditioned one, dry the lock completely by leaving in the sun or using a hairdryer etc, then instead of oiling the lock you GO ASHORE for fire safety reasons and melt paraffin wax in some old washed out tin can (beans, soup or whatever) and submerge your opened locks into the liquid wax and move them around for a minute to ensure the wax gains access to all interior mechanisms by stirring, and flipping the locks.

    You can remove the locks and let them cool, but this allows much of the wax to drain off the still hot lock so I prefer to remove the tin from the heat and allow the entire works to cool and almost solidify before breaking the wax off the locks then closing the shackle and using the key to open and close it a few times to minimally clear the key-way of wax.

    The wax coats every surface providing lubrication, corrosion and temperature protection, and has the added bonus of being dry and clean to handle thereby not causing an oily greasy mess on your hands every-time you handle the lock.

    A block or two of Paraffin is cheap in the canning supplies section of the supermarket and you can use the solidified paraffin /candle wax to lubricate hinges, drawer slides, and squeaky floorboards in the sole as well as using it to waterproof your baseball cap if you are so inclined.

Speak Your Mind