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	Anchor chain locker repair Repairs to Starry Night's anchor chain locker to improve chain handling and replace rusted steel
		The first  signs of trouble could be seen several years ago -  about twelve months after we had had the hull and superstructure repainted. The boatyard who had done the paint job thought the blisters were due to a reaction between the paint and some old filler, and repainted the affected area under warranty. No-one thought to take a look the other side - inside the anchor chain locker. It wasn't until this summer that we realised the problem was due to rusting from within the anchor chain locker. We had never used the anchor except as a means of security when moored on the Thames. This Summer's cruise was to be our first serious attempt at learning the art of staying put. It was while checking to make sure that in emergency  we could cut  the connection between the chain and the boat, that we discovered the truth. There was a huge amount of rust in the locker - whole handfuls of the stuff in great  wafers. Now a small thickness of steel can produce one heck of a lot of rust - there are a few useful websites to be consulted on this subject. Opinions varied between a factor of 12 and a factor of 50. But even so it was worrying. And rust (a small patch) was visible on the outside! After giving the hull some serious  thumping  in the affected area, it was felt that  the problem was not life threatening and  we proposed to carry on with our plans. We would limit the use of the anchor to the broads and fresh water, keep an eye on the situation, and get a proper repair done when we got home. We discovered on the broads that anchoring  was hampered by the chain getting tangled. On weighing anchor the pile of chain in the locker  would get too close to the chain pipe and would prevent the whole chain being stowed. It meant that someone would have to manhandle the heap of chain to let more in. Then when paying out the anchor chain it would get tangled. So we vowed to get this fixed at the same time. A shorter chain pipe and sloping locker floor? On the way home we made some phone calls to various Thames boatyards and quickly found that Nauticalia at Shepperton Marina had experience of repairing anchor chain locker corrosion on old Stevens steel boats.  (obviously a design defect!) They were well able to explain what the problem was and how it could be repaired based on previous repairs done.  So we put it in their hands to do the job. The first step was to cut out the gas bottle locker  which on our variant of Stevens sits in the centre of the bow and hangs down into the chain locker - this would enable proper access to the interior of the chain locker. Then a larger chain locker access panel was created inside. The badly corroded steel was cut out, and remaining corrosion removed with a needle gun. Then came the job of rebuilding the hull and chain locker structure, shortening the chain pipe, putting in a new gas locker and preparing the steelwork for paint. Four coats of primer, three undercoats and then four coats of top in two lots of wet-on-wet. Here was where the problem arose - getting a good colour match. The paint used in 1999 had been specially mixed - we knew the make but not the mix, and had no spare paint in sufficient quantity. The company who painted Starry Night in 1999 had ceased to exist. So Linden Lewis Marine  had to do a trial and error matching exercise. They eventually hit on a mixture of two different Blakes whites to get the right white. It looks good, and the paint line is hardly visible. The inside of the locker was done in the kind of black paint used on the bottom of a narrow boat. Should take some abuse! The finished chain locker has a more pronounced slope towards the drain, and has a shorter chain pipe. A couple of stainless steel shrouds now adorn the bow where the chain and gas locker drains penetrate the hull.		rust visible outside - circled the worst affected area - the port bow - scene of the original paint blister corroded steel cut out and lying on the workshop floor - includes chain locker bottom and part of locker bulkhead the finished job - as good as new or better! A Useful Guide to avoid panic! From Tips on Painting Structural Steel by DK Turner - "Assess coating failures carefully. The volume of rust forming on structural (carbon) steel is approximately sixteen times the volume of the steel sacrificed, i.e., 1 mm of steel produces a 16 mm layer of rust. Therefore assess the thickness of steel remaining not the amount of rust removed." (phew!!!! )
Updated 12 February 2009	back to top