Monday 31st Jan. to Sunday 6th Feb. 2011
So many good things have happened this week.
For the boat it was a jolly good blacking and for V and me it was a break from the boat.
We didnt have the baseplate treated on this occasion but while I was once of the opinion that the bottom plate didnt rust because there was no oxygen down there I now think differently. This photograph was taken a few minutes after pulling out of the water and shows a rusted and pitted baseplate.
Incidentally the bottom plate was last blacked in 2007 and theres still evidence of it on the forward half of the boat and no sign of rust there.
Lifting the bow thruster weed hatch revealed some nasty corrosion in the tube. The snails have gone but the bubbling metal is worse this year. Fortunately this thruster tube lives in a water-tight compartment so we shouldnt sink if it is holed.
By the sixth day the blacking was done and Balmaha went back into the water ready for another year of canal cruising, with her submerged steel protected from the elements.
Mid week we were taken through the city shops to an outlying village to be spoilt rotten with good food and a sleep-over at Mike and Jos (Sarah-Kate).
Part of our break from the boat included a visit to Melton Mowbray to a manufacturer of LEDs lights. While V did MMs Co-op, Mike and I called on Aten Lighting. If its not on the trolley then it can be made to suit the customer so theres no excuse for not having LED lights in every ceiling, wall and gunwale fitting.
I bought a strip of stick-on lights for experiments while Mike ordered some specials for Sarah-Kate.
Look out for Aten Lighting at Crick and Caravan/Motorhome exhibitions, theyre a family firm and make their own lights.
Saturday morning on one of the windiest days of the year Balmaha slipped back into the water to begin her first cruise of 2011. Destination: Barrow for water and a mooring. But, oh no, its a dead tap.
Been out of action for months, a local boater told us, the cold spell last year did nasty things to it and although BW have been prompted the tap is still OOA.
Nothing for it but to head off down to Luffy. V made the comment that Loughborough is the first water point after Kilby Bridge for boats going through Leicester. Is there any surprise that boaters shun Leicester. Thirsty hire boaters – be warned.
Cruising the river Soar was brilliant, the wind blew us sideways, the sky threatened rain and there was hardly a soul about. We couldnt control our smiles.
Were not in a desperate hurry now so theres time to read books or fix broken gadgets. Some days you get a spare couple of hours but you dont feel like doing anything apart from reading books. Ive a pile of them in the corner begging for some attention. But other days the mind cries out for a soldering iron and electronic components and this week is just one of those. A broken ipod, pda and battery tools have queued long enough.
Appendix, re: Blacking.
Quite unconnected with all the above I have seen someones thoughts on possible boat blacking problems which takes the view that galvanic action contributes to the failure of bituminous blacking, which may be combated by adding anodes.
Something about this doesnt sit comfortably with me.
Firstly, one of the purposes and possibly the main purpose of covering a submerged steel hull in bitumen is to separate water from steel. This prevents corrosion – rust.
Secondly, bitumen is an electrical insulator in that it provides a barrier to direct current (DC). This means no electrolysis or galvanic erosion takes place because the metal can not make contact with the electrolyte – water.
Thirdly, sacrificial anodes only provide a protection service for exposed metalwork, for example the propeller.
Only when the bituminous coating is scraped away, and lets face it we all have done that at sometime, is the exposed steel of the hull affected by corrosion (rust), erosion (galvanic or electrolysis) and anodic action (plating).
By this time my daughter Kass will have switched off and gone to bed.
Our anodes showed no acceleration in wear, their reduction is hardly noticeable since last inspection. This indicates they were doing nothing out of the ordinary in providing cover for exposed metalwork. Some would rightly point out that a lot of that depends on the conductivity of the water. Canal water is a bad conductor so little anode wear takes place whilst salt water is a relatively good electrical conductor hence bright white plating of exposed metalwork in quite a short time within a foot or two of anodes.
But one consideration that is often forgotten in the failure of a bitumastic coating on a boats hull is the condition of the surface it is applied to. Moisture on the steel at the time of application doesnt disappear as if by magic, it remains under the bituminous coating keeping the bitumen soft. If you want an example put your used blacking brushes in a can of water overnight and in the morning shake off the excess and theyre ready to go again, bristles as soft as when they went in the water the night before.
An example might be the problem of laying blacktop (road surfacing) in the winter. If the blacktop is laid after rain then on the arrival of the summer sun a two inch thick layer of road surface will easily lift into bubbles a foot across making the road undrivable.
Any amount of post application drying wont release trapped moisture since bitumen is all about preventing the passage of water whether that is towards the steelwork or away from it.
Theres an excellent website for those of us trying to understand what happens to boat hulls in water, both galvanic action and anodic protection, at Smartgauge Electronics.
Theres also lots of info on boat batteries and enough to satisfy the most inquisitive on the subject of Perkert (sorry, Peukert**).
Remember, next time youre in the pub, why not put aside customary discussions on boat toilets and reflect instead on Peukerts Equation.
** Thanks Paul.