Photos of pitting on hull from survey

[Jamesl9]

Hi, below are photos of pitting discovered on a hull survey on a 57 ft narrowboat built in 2007. The survey report says there is a small amount of deep pitting on the side plates and some other pitting measuring upto 0.9mm, and the deep pits require back filling with weld. The photos are of both the deep and upto 0.9mm pitting after the hull has been jet sprayed.

 

The hull readings taken are all ok and there's only been minor diminution of plate thickness.

 

I'm trying to get opinions on the severity of the pitting if possible based on the photos.

 

Unfortunately it won't let me upload the individual photos because they're above the maximum allowed size limit so I've had to take a screenshot of all 14 images. Not sure if they will be clear enough.

 

Thanks.

[Alan de Enfield]

That looks pretty extensive - did the surveyor speculate on the reasons ?

 

Has the boat lived in a marina ?

Does it have a GI or Transformer ?

[Jamesl9]

21 minutes ago, Alan de Enfield said:

That looks pretty extensive - did the surveyor speculate on the reasons ?

 

Has the boat lived in a marina ?

Does it have a GI or Transformer ?

No, the surveyor doesn't answer my calls or reply to messages now he's sent the report. I had to turn up at the marina myself to get these photos as I couldn't get an answer about how many deep pits there were (the report just says a small number).

 

The boat was on a private mooring and doesn't have a GI or transformer.

[David Mack]

Silver colouring in all the pits whereas the unaffected steel is black suggests some live electrochemical effect is happening. If the boat has no GI or isolation transformer but is left plugged into a mains supply that could well be the cause. If no mains supply at all I would at least want to check that there is only one single connection between battery negative and the hull, as stray currents flowing on the hull could have contributed to the corrosion.

[Jamesl9]

9 minutes ago, David Mack said:

Silver colouring in all the pits whereas the unaffected steel is black suggests some live electrochemical effect is happening. If the boat has no GI or isolation transformer but is left plugged into a mains supply that could well be the cause. If no mains supply at all I would at least want to check that there is only one single connection between battery negative and the hull, as stray currents flowing on the hull could have contributed to the corrosion.

The deep pits are due to be welded in the next couple of days, I'm not sure if they have already been prepared ready for welding? It's the first boat I've purchased and is for sale for £52k. After seeing the hull condition I'm wondering if I should withdraw from the purchase.

[booke23]

After you get the deep pits welded you should also consider having it 2 pack epoxied. That should at least preserve the hull in it's present condition. 

[Jamesl9]

I've just worked out how to resize the photos 😅. The surveyor concluded in the survey report that once the minor defects are delt with it represents a well appointed narrowboat. I'm not knowledgeable enough to confirm if this is true or not.

[Tracy D'arth]

Some of those pits were deep before it was blacked last.

I have seen far worse  and if the welder is conscientious  and gets all the deep ones, and you get it grit blasted and epoxy coated It should be fine for many years.

I too would suspect an electrical cause. Larger shallow pits are usually just normal corrosion, deep small ones are usually an electrical fault or microbial corrosion.

What condition is the base plate or are some of these pix from underneath?

I would be looking for a substantial price reduction.

[Jamesl9]

12 minutes ago, Tracy D'arth said:

Some of those pits were deep before it was blacked last.

I have seen far worse  and if the welder is conscientious  and gets all the deep ones, and you get it grit blasted and epoxy coated It should be fine for many years.

I too would suspect an electrical cause. Larger shallow pits are usually just normal corrosion, deep small ones are usually an electrical fault or microbial corrosion.

What condition is the base plate or are some of these pix from underneath?

I would be looking for a substantial price reduction.

All of the photos are from the sideplate. The base outer readings are 7 at the lowest but mainly between 8 to 9.6mm, the base midsection readings are all between 9 to 10mm. The surveyor hasn't reported any pitting on the base. For £52k would you class the hull unacceptable? Thanks

3 minutes ago, Jamesl9 said:

All of the photos are from the sideplate. The base outer readings are 7 at the lowest but mainly between 8 to 9.6mm, the base midsection readings are all between 9 to 10mm. The surveyor hasn't reported any pitting on the base. For £52k would you class the hull unacceptable? Thanks

Sorry for so many questions but would this be classed as extensive pitting?

Edited October 28, 2023 by Jamesl9

[Karen Lea Rainey]

It looks to me like, there are many equally as worrying 'pits' holes/ previously blacked that have not got any worse since the last blacking.

Do you know when it was last blacked?

In almost all of the pictures, the bitumen stopped any further corrosion,  you could choose to black it every 2 years and it will stall any advancement of the pits,, / shiny silver rash. The wholes look more troublesome and a few look quite deep.

Definitely address them now, plus 3 coats of blacking, look to reduce the cost by another 3 to 5k, that is if you like the boat.

It has definitely been plugged in long term on a mooring and fizzling away like a lozenge.

Extra Blacking, spot welding, 6 to 8 new anodes plus the risk is worth the 3k reduction, plus what else did your surveyor find.

It's quite a young boat at 2007 in my view to need so much work and probably not blacked since 2016 in my view.

[Jamesl9]

1 hour ago, Karen Lea Rainey said:

It looks to me like, there are many equally as worrying 'pits' holes/ previously blacked that have not got any worse since the last blacking.

Do you know when it was last blacked?

In almost all of the pictures, the bitumen stopped any further corrosion,  you could choose to black it every 2 years and it will stall any advancement of the pits,, / shiny silver rash. The wholes look more troublesome and a few look quite deep.

Definitely address them now, plus 3 coats of blacking, look to reduce the cost by another 3 to 5k, that is if you like the boat.

It has definitely been plugged in long term on a mooring and fizzling away like a lozenge.

Extra Blacking, spot welding, 6 to 8 new anodes plus the risk is worth the 3k reduction, plus what else did your surveyor find.

It's quite a young boat at 2007 in my view to need so much work and probably not blacked since 2016 in my view.

I'm told it was last blacked in 2019 but can't confirm the date is correct. The only other issue was damage to the propeller blade which should be looked at if there's any vibration or singing when cruising.

I'm very suspicious of the surveyor now considering he didn't mention anything to do with electrical corrosion when 4 posts on here within a couple of hours have noticed it straight away just by looking at the photos.

As bitterly disappointing as it is I think I'll have to cut my losses, withdraw from the purchase and start again at square one 😞

[LadyG]

4 hours ago, Jamesl9 said:

No, the surveyor doesn't answer my calls or reply to messages now he's sent the report. I had to turn up at the marina myself to get these photos as I couldn't get an answer about how many deep pits there were (the report just says a small number).

 

The boat was on a private mooring and doesn't have a GI or transformer.

Whats his name, so others can avoid him....

[Alan de Enfield]

31 minutes ago, Jamesl9 said:

I'm very suspicious of the surveyor now considering he didn't mention anything to do with electrical corrosion when 4 posts on here within a couple of hours have noticed it straight away just by looking at the photos.

 

There is always the possibility that it is not 'electrical' corrosion / erosion but is Microbial, which is why I asked if the surveyor commented on  a posible cause.

 

 

[Bee]

To be honest I would not be very happy with it. About 5 pics up from the bottom there looks to be a slight weep from the seam that joins the bottom to  the side. I would also expect to see some numbers chalked on the side as well by the surveyor indicating the thickness. To my eye it looks as though a good clout from a hammer on to a centre punch could go through some of those pits. Also unless there is something odd going on I can see no reason why the bottom plate should be any different. I am surprised that a boat from 2007 is showing such pitting and also that it appears that it was pitted last time it was docked and painted and a few years younger. If all steel boats had this sort of life expectancy then I reckon plywood could see a resurgence in popularity.  Sorry to be a doom merchant but hopefully the next boat will be better. Good Luck.

[matty40s]

3 hours ago, Jamesl9 said:

All of the photos are from the sideplate. The base outer readings are 7 at the lowest but mainly between 8 to 9.6mm, the base midsection readings are all between 9 to 10mm. The surveyor hasn't reported any pitting on the base. For £52k would you class the hull unacceptable? Thanks

Sorry for so many questions but would this be classed as extensive pitting?

Ok, I see many boat hulls, and those pits, and some surrounding are worrying.

The fact that he will not contact you back(having taken £500-£1k)off you, is disgraceful.

They are probably microbial rather than electrical, (still active when dry seeing the silver) and unless the hull is bleach treated before blacking, will continue to eat your hull until you get wet feet and lose your insurance no claims.

It does need them filling, and chances are, the heat will kill the local swarms, but will not stop the others attacking other areas on your hull.

Baseplate will be the same whatever your surveyor says(it will not have been power washed, and will have been inspected within 6" of the side.

 

If it were my potential boat, I would taking it to Debdale for the full treatment...with a bleaching. Cost probably around £6-7k

Edited October 28, 2023 by matty40s

[Mike Adams]

I would pull out of it as you cannot be sure of the cause and if it were to continue it would make the boat very difficult to sell on. I have seen the odd pit like those deep ones but not to that extent. Hull condition and construction are fundamentals for a narrowboat. Forget the fancy painting and interior. I would just move on.

[Jamesl9]

1 hour ago, Mike Adams said:

I would pull out of it as you cannot be sure of the cause and if it were to continue it would make the boat very difficult to sell on. I have seen the odd pit like those deep ones but not to that extent. Hull condition and construction are fundamentals for a narrowboat. Forget the fancy painting and interior. I would just move on.

I've decided to pull out. The fact the surveyor wouldn't answer my one enquiry regarding the extent, depth and location of the pitting made me suspicious. I then had no option but to ask the brokerage/marina who were also going to do the work recommend by the surveyor.. they simply told me there would be 6 welds to the deep pitts. I was only able to get the photos of the hull today (as the surveyor didn't put any on the report) when I turned up at the brokerage/marina drydock out of the blue and took the photos myself. I could be wrong but the surveyor doesn't seem to be acting in my best interests by saying there's 'a small number of deep pitts that require welding' on the report then not answering telephone calls or replying to messages. I appreciate the help from the Canal World forum and will keep updating and adding more details.

Edited October 28, 2023 by Jamesl9

[MrsM]

No photos in your survey report? That sounds very odd. 

[David Mack]

52 minutes ago, Jamesl9 said:

 I could be wrong but the surveyor doesn't seem to be acting in my best interests 

Did you choose the surveyor or was he recommended by the broker?

[Jamesl9]

4 hours ago, David Mack said:

Did you choose the surveyor or was he recommended by the broker?

The broker gave me the details of 3 surveyors, he was 1 of the 3. I did try 2 other surveyors before but they weren't available.

[BWM]

The surveyors report appears to favour the seller in my opinion and has undersold the pitting. Would be far better to spend a similar sum on a boat with a pristine hull and some decorative/interior issues. 

[Tracy D'arth]

More pertinent, I can see no ground off areas where ultrasonic thickness measurements have been taken in any of the photographs. Not my sort of survey.

Judging by the amount of blacking still on it has not had a powerful washing of either, very suspicious.

Edited October 29, 2023 by Tracy D'arth

[Jamesl9]

18 hours ago, Alan de Enfield said:

 

There is always the possibility that it is not 'electrical' corrosion / erosion but is Microbial, which is why I asked if the surveyor commented on  a posible cause.

 

 

A number of options from people I've spoken to today believe it could well be microbial because of the appearance. I can't understand why the surveyor didn't mention any of this in his report. I was told today if it is microbial it can be treated. However I'm not sure if welding the pits and blacking would solve the problem.

[Alan de Enfield]

59 minutes ago, Jamesl9 said:

A number of options from people I've spoken to today believe it could well be microbial because of the appearance. I can't understand why the surveyor didn't mention any of this in his report. I was told today if it is microbial it can be treated. However I'm not sure if welding the pits and blacking would solve the problem.

 

When I first saw the photos my feeling was that it was Microbial Corrosion which is why I asked if the Surveyor had made any comments - the existence of MIC has, until quite recently, been denied by the 'Inland boat industry, from boat builders to boat surveyors. As it has become more prevalent more and more people now acknowledge it is "a fact of life"

 

Some of the 'old timers' on this forum have been the most active of the 'MIC deniers', but time and evidence has started to convince them.

 

If it microbial it is not easy to remove and treat to avoid it coming back - an extract from an article on the subject :

 

 

Boat owners and yards know all about rust. There is endless literature on electro-chemical and galvanic corrosion – all under the general heading of ‘rust’. But there are other types of corrosion which closely resemble (but are not) rust in the conventional sense about which little is known by boat owners and by many yards. This is a corrosion caused by microbiological action which is can occur on boat hulls, particularly those lying in canals or rivers containing high levels of chemicals or decaying vegetable matter. 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

 

If a hull is found with evidence of microbial attack, it is necessary to deal with it to try to prevent it recurring. A simple solution is for the whole area to be washed with copious amounts of high pressure fresh water. When dry the area affected should be coated with a strong bleaching agent (sodium hypochlorite) diluted 1:4 with water and left for twenty four hours. Afterwards a second high pressure fresh water wash is necessary followed by recoating. This will probably remove around 90% of the microbes but the only real solution is to blast back to bare steel and to treat any inaccessible areas such as tack-welded rubbing strakes as best one can with the bleach solution before applying the next stage of the coating process. 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..