Alan de Enfield

Practically, for the inland waterways boaters, it is "does it look like, and sound like the description and pictures of MIC" ? Then take preventative action anyway whilst the boat is being taken back to bare metal (Bleach doesn't work if the boat is still covered with blacking etc, as MIC 'tunnels' along underneath the paint) The AI answer to the way that big ship owners identify it is : Microbiologically Influenced Corrosion (MIC) Microbiologically Influenced Corrosion (MIC) is a form of corrosion caused by microorganisms. To identify MIC, a combination of chemical, biological, and metallurgical analysis is required. Here are the key steps involved in the identification process: Sample Collection: Samples should be taken wet and prevented from drying to ensure the presence of biofilms and fluids containing the requisite microorganisms. Sample Analysis: Common molecular microbiological methods include qPCR, DGGE, and metagenomic sequencing. These methods require small sample sizes and can identify microorganisms even when they are not alive. Metabolic Activity: The metabolic activity of each microorganism under similar conditions must be determined, as simply measuring high concentrations of microorganisms is not sufficient. Synergy Analysis: Microscopic techniques can determine the concentrations of microorganisms, and together with x-ray diffraction of the corrosion products, the level of synergy can be determined. For internal pipeline surfaces, NACE TM0212 outlines the molecular methods for evaluating MIC, microscopic analyses, sampling, and chemical assays. It is necessary to analyze water chemistry to determine the species that support microbial metabolism and growth, including sulfate, acetate, or organic compounds, as well as abiotic factors like dissolved oxygen or sulfur.

Are you sure it was water and not MIC excreta which travels underneath paint and forms blisters. Microbially Induced Corrosion (MIC) is a highly unpredictable process but under the influence of micro-organisms, corrosion processes can be rapid, happening in a matter of months compared to the years it would take for ordinary abiotic corrosion to reach serious proportions. This phenomenon is well known in the oil, gas, water and mining industries but is little understood in the steel boating world. MIC frequently occurs in areas with high nitrate content in the water – this particularly pertains to arable regions of the canal network and particularly to canals and rivers on the east side of the UK and where there is intensive crop farming using non organic chemical fertilizers with consequential phosphate, sulphate and nitrate run-off into the watercourses. Marinas fed by rivers are another risk area and, in salt water environments, it is well known that harbour muds are highly contaminated by sulphides produced by these creatures. Sulphide films are, by their very nature, highly corrosive and the identification of such very obvious. It is usually found under muddy and slimy surfaces, sometimes even behind paint coatings and a very careful visual inspection is necessary to locate it. It is not discoverable by non-destructive testing such as ultrasonic thickness measurement, eddy current testing or the magnetic method familiar to most marine surveyors. The bacteria are often found inside oxidised welds or in areas which contain physical defects such as porosity, overlap or lack of penetration. The microbes leading to this condition can both cause corrosion from beneath existing coatings or seek out pinpricks in the steel coating and cause the reaction to occur from the outside. MIC bacteria can be present under previous blackings and is not eradicated by simple pressure washing. Unless correctly treated, MIC can continue to thrive beneath the coating, emerging as major pitting. The main problem is that the microbes can continue to live beneath the existing paint coatings and once sealed in with a fresh blacking, the lack of oxygen and light is the perfect environment for them to thrive leading to a risk of corrosion from the inside out. No coatings are entirely proof against a microbial attack from the exterior. Minute pinpricks, mechanical damage below the waterline are all opportunities for the microbes to penetrate the steel and commence the process from the outside in..

Because I'm not sure it looks like MIC, - mind you if it has been 'polished' down to almost bare metal it may have removed much of the evidence. But, the 'litte pits' do not look correct for MIC, they look 'black' in the pit whilst MIC pits are 'bright shiny silver'. The OPs 'pits' Never say never - the pits could be partly filled with 'black dust' (covering the 'shiny silver MIC) following the grinding down of the old blacking / epoxy. It certainly looks to be a very pitted hull, but difficult to tell the depth of them. It may be worth having them looked at whilst in the dock and before you start re-coating.

Looking at those pictures you need to go back to bare metal and start again. If you just 'go over it' you will have wasted you money as it falls off within weeks.

That may limit its appeal as more and more cities introduce similar rules.

Lloyds explanation ................... There was a thread discussing the changes in 2021, where I posted an extract from a letter I received. (It was also around that time that our 'overseas' owners started to have problems insuring GB based boats). "For the first time in over 200 years in the history of Lloyds, special measure have been imposed demanding that all Syndicates writing Yacht insurance submit a sustainable business plan, in the absence of which they would be precluded from writing this class of business. This is because the market has spiralled down to a fundamentally unsustainable level of rates resulting in consistent attritional underwriting losses compounded by catastrophic (storm) claims. ........................................ ............................. we continue to write yacht business but we are now instructed to increase rates. All insurers are following suit except those who are now precluded from writing yacht insurance ...............................

Certainly Lloyds did that a few years ago and refused a trading licence to quite a lot of insurers and brokers (previously) offering boat insurance, when they considered their business plans unrealistic and the business unsustainable. If SAGA as one of them I don't know

Haven Knox Johnson are "30 years and every 10 years afterwards". They are not the cheapest but you get what you pay for, and, you save paying (maybe) £1000-£2000 for lift out and surveys every 3 years.

But, it should always be a concern and taken into consideraton - particularly as several forum members have experienced the effects of microbial attack where the steel went from 8mm to 2mm in 18 months. The worse case recorded was on a 'big ship' where it 'lost 22mm in thickness in 12 months. MIC has always been 'shrugged' off by the inland waterways industry, but surveyors now are suggesting that some 85% of steel boats on the canals are affected to some degree. Some canals are worse than others, and it seems that 'agricultural run-off' can be a major contributory factor.

I have an underwater air horn which is worn on your BCD when diving - but - it is not automatic, and, it requires a 150psi air source.

You have been knocked unconscious - as you fell in, your head hit the pontoon, lock wall, side of a boat etc. Thats why we wear auto-inflate lifejackets !

It now sounds very much like the standard BMF brokerage sales contract. BUT they all say they do this: ".....all moneys deposit and balance are held in a “client trust account”. “Separate and distinct from the brokers own monies”. But, in reality, (Maybe not the broker you are dealing with), there are a number who do not actually do it - and no one enforces it until the broker cames on 'hard times' and dips into the client-account and we have another example of the 'Nottingham Broker' There are an increasing number of Phoenix companies who 'go bust' and set up again with a new name

You can buy the water activated device that inflates a lifejacket for about £3 to £5 on aliexpress with a bit of ingenuity I bet you could attach it to a horn similar to that on the hand held 'air horn' Add a 16gram CO2 cartridge and "Robert is your mothers brother"

And, recent history in the South West, and South East suggests that mains-water consumers should be concerned.