Monthly Archives: November 2015

  • 91. Top Tips Tuesday - Protect Your Threads - Galling

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    Last Tuesday in my TOP TIPS TUESDAY blog the headline I used was ‘Stainless Doesn’t Rust (or does it)' I then went on to talk in the article about crevice corrosion, and I also stated that crevices can form under welds, WRONG* (but more about that later!)

    Galling is the term used when two surfaces in contact seize up as a result of cold welding. The problem (also known as adhesive wear) is most common in materials such as stainless steel and we in the marine trade come across it occasionally where you have stainless rigging screw body** and a stainless stud or fork. To help prevent galling make sure that the two surfaces are clean and free from any contamination, do NOT use a mild steel brush to help you clean the threads; consider the Shurhold Detailing Brush which has stainless steel bristles and a squirt of WD40. My recommendation after cleaning is to use a lubricant such as Lanocote or Selden Rigging screw oil to lubricate the threads.

    ** most good turnbuckles these days either have a chrome plated phosphor bronze body, or if the body is stainless there is a bronze threaded insert both ends which prevents galling however, threads should still be clean before adjusting.

    Incidentally when mooching round our local boatyard a couple of years ago I came across these very simple homemade covers (made from old bits of hose pipe) for protecting the threads and help keep them clean.

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    Some skippers of course leave their mast up when lifting out, me, I prefer my mast to be down and then you get the chance to check everything out, rigging, nav lights, mast head equipment etc and of course all the fastenings used to hold the fittings in place.
    As a consequence of last weeks article I did get a response from an ‘avid reader’, a retired metallurgist, who wrote and I quote "Your summary of the significant subject of crevice corrosion is fine - that is it is caused by a lack of oxygen in the crevice leading to a breakdown of the oxide film (chromium oxide) that gives stainless steel its corrosion resistant properties (see below image showing the results of crevice corrosion).
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    * However you also mention corrosion associated with welds. This is commonly known as weld decay and is brought about by the heat of the welding process causing the chromium present in stainless steel to combine with any carbon present to form chromium carbide - thus depleting the steel in the vicinity of the weld of its essential chromium. (Lose the chromium and you say goodbye to any corrosion resistance). This problem can be overcome, at a cost, by adding titanium to the alloy. Titanium has a greater affinity for carbon than does chromium, hence mopping up the carbon to form titanium carbide and thereby leaving the chromium behind to do its corrosion resisting job". Thank’s to Peter Baylis for putting me right!
  • 90. Top Tips Tuesday - Stainless Doesn't Rust! (Or Does It?) - Crevice corrosion

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    We all take our stainless steel fittings for granted, after all stainless doesn’t rust or does it? Stainless steel, as you probably know, was ‘discovered’ like all great things in the world in Great Britain by Harry Brearly and yes I have been known to rant on about the Hovercraft, the Harrier Jump Jet etc etc.

    However let’s get back to stainless. Keel bolts, for example when buried in timber are in a non-oxygenated environment and thus the corrosion resistance can be adversely affected likewise the fastenings used to bolt a pintle(s) or gudgeon(s) to a wooden rudder.

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    Now to get a bit more technical:

    Crevice corrosion is a localised form of attack which is initiated by the extremely low availability of oxygen in a crevice. It is only likely to be a problem in stagnant solutions where a build-up of chlorides can occur. The severity of crevice corrosion is very dependent on the geometry of the crevice; the narrower (around 25 micro-metres) and deeper the crevice, the more severe the corrosion. Crevices typically occur between nuts and washers or around the thread of a screw or the shank of a bolt. Is this the reason the anchor swivel failed?

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    Crevices can also occur in welds which fail to penetrate and under deposits on the steel surface.

    Now here’s an interesting one, self assembly rigging terminals from manufacturers such as Sta-Lok or Petersens. At Sta-Lok they used to write (nowadays its personal preference) that for ‘interior waterproofing, you should unscrew the two parts and insert a blob of silicon rubber about the size of a grape on the former inside the bottom of the end fitting before assembling, Petersens don’t believe in filling the fitting with silicon, they reccomend regular flushing with fresh water.

    Our recommendation is that at this time of year, go over all your stainless steel shacklesswivels, rigging screws etc with a fine tooth comb and check their integrity, if the mast is down likewise all mast fittings. If the mast is still up and assuming the wind abates before it gets too cold up you go in a bosuns chair and check out all the stainless fittings.

    If you want to bring your stainless back up to a ‘new look’ there are a number of excellent polishes on the market. Vistal works well and can be used with success on a number of other substrates. Shurhold Magic Wool is an excellent product for a wide variety of surfaces and of course there is the excellent Daveyshine high performance metal polish. If abroad where temperatures are in general warmer, Spotless Stainless is my favourite. Why? Because there is no work involved! Paint it on, (suggest you crack open a can at this stage) leave and as long as its not allowed to dry out  your stainless will look like new in no time!

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  • 89. Top Tips Tuesday - Gadget Saver - Saves Your Electronics From A Watery Death!

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    After, dare I say it, over forty odd years in the marine trade perhaps I can be forgiven for at times being more than a little cynical when the sales manager of a major marine wholesaler runs through his sales pitch! However, when introduced to the Gadget Saver the other day and then having watched the video and read the independent review on www.mybroadband.co.za I think, like flares, every boat that goes to sea should have at least one if not two (small/ 45g for mobile phones, car keys and other devices up to 10x15cm, the larger/75g for electronic tablets etc up to 18x24cm). The Gadget Saver does what is says on the packet ‘dries out wet electronics-rapidly' Not only will I be putting a couple on our boat but each of my lovely daughters will be getting one as a stocking filler this Christmas as both have a habit of dropping iPhones in the bath!

    Ps. Izzy our efficient young Saturday girl is also getting one as part of her Storrar Marine ‘Christmas Box’ told me the other day that two of her phones have ended up in the toilet

  • 88. Top Tips Tuesday - Winterising Your Marine Engine

    Following on from our previous Tips and Advice on Laying Up For Winter, this week Andy looks at Engines and Winterisation covering both Inboards and Outboards.

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    Inboards:

    At the end of the season we strongly recommend that you fill your diesel tank to the brim as this will help prevent a condensation build up, however, before doing so we suggest you also add the appropriate amount of diesel fuel additive like Marine 16. This, along with the full fuel tank, will help prevent the dreaded diesel bug.

    So, should you do your oil change now? Most experts prefer to do it at the end of the season, some say “best in the spring”, but  all agree that you should run the engine under load (in either forward or reverse gear) for at least twenty minutes before draining the oil and changing the filter. This warms the oil making it easier to remove as well as putting any particles into suspension in the oil so they are removed at the same time. Our mechanic has always used a Pela vacuum pump to remove the oil which is retrieved via the dipstick hole. It’s sucked straight into the pump’s container which lessens the chance of a spillage. Not quite so robust is the Seago Extract-It but it was still awarded best buy by PBO. On a tight budget? Consider the traditional brass cylinder type this may be the answer, however you do need to collect the oil in a separate container! If you are like Rob (of advancing age and suffering from arthritis in the wrists) and have difficulty in undoing the oil filter, the Boa Constrictor strap wrench takes the pain away!

    If your boat is being stored on dry land, once she is up on the hard stand we suggest that you close the water inlet seacock, open the water filter and with the engine running pour in an appropriate antifreeze mix. Carry on pouring till you can retrieve the mixed antifreeze from the exhaust outlet. Once you have done this, stop the engine and turn off the diesel tap. If you intend to leave your boat in the marina or on moorings don’t follow this procedure with the antifreeze as you will pollute the water. In this case we would recommend draining the seawater system. Next, disconnect the starting circuit from the battery and consider taking all batteries home and storing in a warm place, however, if you are leaving the boat on the water make sure there is still a battery to run the bilge pump!

    If the engine could do with a clean, consider cleaning it down with an engine cleaner and degreaser, this will remove any ingrained grease and grime. Don’t forget to keep on top of any rust spots; surface should be prepared with the appropriate primer than follow up with the correct colour paint. Spray all exposed parts of the engine with Quicksilver Corrosion Guard  then get a couple of oily rags and stuff them up the exhaust pipe and engine air intake.

    If you have access to shore power a tube heater will stop any moisture from freezing as it circulates warm air round the engine bay. Check, however, that a heater can be left unattended; some yacht clubs don't allow heaters to be left unattended in their boatyard.

    At this time of year it’s worth checking the condition of all water hoses and belts. Check the impeller (out of sight out of mind), the engine anode and of course the thermostat. Incidentally, to check a thermostat is working all you have to do is remove and place in a bowl of boiling  water and check it activates, depending on the make of engine it may either open or close when placed in the hot water so make sure you check the status before you drop it in. Throttle and gear shift cables can snap where the cable exits the outer casing so examine closely by gently flexing the cable and check for broken strands. If old, stiffness in the operation may mean the beginning of cable failure. Check along the full length of the outer casing for any signs of damage.

    Finally, for what it costs, a replacement primary and secondary fuel filter should be fitted regardless of the condition of the old. If you are using your onboard spares stock, don't forget to replace the spares whilst it's fresh in your mind.

    Outboards - 4 Stroke

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    Clean the engine down with something like Yamalube Pro-Active Cleaning Gel, let it soak in then wash off with fresh water. Add the correct amount of fuel stabilizer to your fuel tank. If you have an internal fuel tank fitted in the boat, the best way to add the stabilizer is to add the correct amount (for the fuel remaining in your tank) to 1 litre of fresh fuel, mix thoroughly then add to the main tank. Next place your engine in a fresh water tank or connect a flushing attachment and run your engine for 15 minutes to get the mixed fuel completely through the fuel system and to remove any traces of salt from the cooling system.

    After you have stopped the engine and disconnected the kill cord, remove the plugs (beware they may be hot) and add a small amount of engine oil into each plug hole. Rotate the flywheel manually to distribute the oil in the cylinders then reinstall the spark plugs. Remove the thermostat and check for correct operation by dropping it into boiling water. Change the engine oil and filter as well as the gear box oil.

    At this stage its worth touching up any exposed alloy surfaces with the appropriate primer and correct colored paint. Spray Quicksilver Corrosion Guard on all external metal surfaces (except anodes). Finally, store the engine upright to allow water to drain out.

    Should your engine be fitted with remote controls and steering, ensure you grease all lubrication points as per manufacturer’s recommendations.

    One thing that’s worth noting is if your engine is still under warranty you need to check the terms as carrying out even basic maintenance like changing oil and filters may invalidate the warranty, particularly where your engine is subject to an extended warranty offered past the standard manufacturer's warranty.

    Outboards - 2 Stroke

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    Clean the engine down with something like Yamalube Pro-Active Cleaning Gel, let it soak in for five minutes and then wash down with fresh water. Add the correct amount of fuel stabilizer to any built in fuel tank(s), however, if it’s a small auxiliary engine with a separate tank or integral tank, empty contents into a petrol engine car AFTER carrying out the following procedure. Either place your engine in fresh water or connect a flushing attachment and run your engine in neutral for 10 minutes. Increase speed to fast idle then disconnect fuel supply. Just before engine starts to stall (and it could run for up to 3-4 minutes!), quickly spray Quicksilver Storage Seal into carburetor until engine dies from fuel starvation. After disconnecting the kill cord, remove the spark plugs (once again beware they may be hot) and inject 1oz of Quicksilver Storage Seal around the inside of each cylinder. Rotate the flywheel manually several times to distribute the oil in the cylinders then reinstall the spark plugs. Remove the thermostat and check for correct operation by dropping it into boiling water. Drain and replace the gear oil and at this stage its worth checking for any bare metal surfaces that may need treatment, first use the appropriate primer followed up with the correct coloured paint. Spray Quicksilver Corrosion Guard on all external metal surfaces (except anodes). Finally store upright to allow water to drain out. Should your engine be fitted with remote controls and steering, ensure you grease all lubrication points as per manufacturer’s recommendations.

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