Grit Blasting

[Laura Bett]

Hi everyone, we are looking to buy a live aboard narrowboat and have been advised that one we have seen may require grit blasting.  Does anyone have any info. on this procedure they could share with us?

[Alan de Enfield]

What was the actual suggestion for saying it required grit blasting ?

 

Grit blasting is simply a precursor to painting the hull.

Has it had a bad survey ?

Does it need overplating or corrosion pits filling ?

 

Who advised it needed grit blasting ?

Was it a qualified surveyor, or a guy passing when you looked at it ?

 

More info and background would be helpful.

[Laura Bett]

Apparently there is pitting damage.  The brokerage have advised grit blasting to see what extent of damage there is.

 

[BEngo]

If you are buying it is not you who should be paying for the grit blasting.  It will cost a couple of £k at least and if you find there are excessive  pits, what then ? The pits are the problem of the current owner.  If they are bad the owner should bear the pain of getting them assessed and repaired or selling at a lower price.

 

The broker is trying it on. If you otherwise like the boat a lot, and you are prepared to risk about £500, get a survey.  Ask the surveyor specifically, in writing, to look at the pitting and make recommendations as to any essential urgent action needed, including where on the boat, and what.  You need specifics, not just some airy recommendation to grit blast and epoxy coat 'in the near future'.  Being specific will not be a problem to a good surveyor.  He may even, probably verbally, give you a guide to costs of the urgent action.

 

If you don't fancy having a survey that may cause you to walk away having spent £500,  walk away now.

 

And be very wary of that broker ever onwards.

N

[Laura Bett]

The price has been lowered.  I see your point on the seller being responsible though.  Can we ask for the boat to be taken out of the water for the survey?  Excuse my naivety, but how does the surveyor know the extent of any damage unless it is out of the water?

[BEngo]

Yes, you can, and should,  ask for an out of the water survey.  The costs of coming out of the water and the  survey fall to you.  The surveyor should  then be able to do ultrasonic thickness testing  probe the pits and pass a professional opinion backed  by evidence.

 

Once you have ordered and paid for a survey the report belongs to you alone, and no one else, except usually your insurers,  can rely on it.  Thus you should not rely on a survey commissioned and paid for by a seller, broker, previous owner or anyone except You.  It is hard enough getting any comeback to a surveyor's report but impossible if you are trying to get comeback to someone else's surveyor.

 

If you say roughly where the boat is folk on here will be able to make suggestions for a surveyor.

 

N

[LadyG]

The broker is confusing you with science, what you must realise is that he owes you no loyalty, he acts for the vendor.

Any boat is a risky purchase, you should be aware of that, and  be realistic about annual costs. Then have a look at a few boats. If you like one look at the electrics, ask if there are paper records. Have a good look for water ingress, staining of woodwork, check round windows and vents. Check for rust, look in engine hole, are hoses in perfect condition etc etc. Check oil on dipstick, no frothing. 

Rust along the waterline is not a good sign. 

The most important survey is the hull, the boat is lifted out of the water, usually washed off to remove weed and debris, then the surveyor will test hull thickness with a meter. He will usually chalk the hull thickness as he goes, and inspect for holes (!), pitting, damage etc. 

Check steering and other things which you have asked for: the more you ask for the more it costs, obviously. 

 

Edited February 17, 2022 by LadyG

[beerbeerbeerbeerbeer]

As an aside, there are a few boat yards that have boats out of water and up for sale. 
Longport always seems to have a few. 
Could save you a few quid and some time IF there’s a boat already out on hard standing waiting somewhere for you. 
🤷‍♀️Just an idea. 

[Laura Bett]

Great advice folks thanks very much.

[Alan de Enfield]

54 minutes ago, Laura Bett said:

Great advice folks thanks very much.

 

As said - you are responsible for all of the costs involved in getting it out of the water, the survey and putting it back into the water.

 

The survey will be ~£500

The cost of lift out / lift in can vary between "a couple of £100" to £200 'each way'

 

Your total cost of finding out the condition of a boat will be around £500 to £900, and if you reject the boat then that cost is 'written off'.

Next time you look at a boat you will have the same costs again, repeat repeat repeat.

 

It can soon eat into you total budget - particularly if you are looking at boats at the bottom end of the price range, (probably ~ £25,000 in todays market) you can end up looking at lower and lower priced boats as your capital is eroded after paying for several surveys - its a never ending spiral - the cheaper the boat the more likely it is to 'fail the survey' ** and the less you have to spend on the next boat / survey, so you look at lower priced boats ...........................................

 

** A boat cannot 'fail a survey', the survey is simply a report on the condition of the boat, only you can determine if the condition and costs to rectify them means it 'passes or fails YOUR requirements'.

Edited February 17, 2022 by Alan de Enfield

[Bee]

7 hours ago, Laura Bett said:

Apparently there is pitting damage.  The brokerage have advised grit blasting to see what extent of damage there is.

 

Hmmmm..... I think I might leave this for the experienced people with big welding sets and filthy overalls who aren't frightened by bad news.

[john.k]

Actually,you dont need a big welding set ......one of the 140 amp inverter sets with decent leads are all I use now.....these things are absolute magic ,and weight a couple of Kgs.....I have Lincoln 400 amp diesels,never use them now ,except for cutting scrap.....Add a couple of battery tools ,and there is nothing on a steel hull you cant repair.

[ditchcrawler]

On 17/02/2022 at 15:00, BEngo said:

Yes, you can, and should,  ask for an out of the water survey.  The costs of coming out of the water and the  survey fall to you.  The surveyor should  then be able to do ultrasonic thickness testing  probe the pits and pass a professional opinion backed  by evidence.

 

Once you have ordered and paid for a survey the report belongs to you alone, and no one else, except usually your insurers,  can rely on it.  Thus you should not rely on a survey commissioned and paid for by a seller, broker, previous owner or anyone except You.  It is hard enough getting any comeback to a surveyor's report but impossible if you are trying to get comeback to someone else's surveyor.

 

If you say roughly where the boat is folk on here will be able to make suggestions for a surveyor.

 

N

I am not sure how the broker can say its pitted and needs blasting unless its already been out for survey and the buyer walked away

[Laura Bett]

I think the buyer did walk away.

[Alan de Enfield]

23 minutes ago, Laura Bett said:

I think the buyer did walk away.

 

That should (maybe) give you a good idea about what your actions should be - they have seen the survey.

[john.k]

If the hulls been inspected,then its likely been  cleaned,and all you need is an underwater camera on a stick.............or if the canal water isnt so foul it will kill you,then get your wet suit on and take a swim.

[syd]

On 17/02/2022 at 13:54, Alan de Enfield said:

Grit blasting is simply a precursor to painting the hull.

 

It's more for pulling the moisture out of the steel, I was told. Helps alot with the interior steel, wear wise.

 

Edit: thinking about it now, I think I'm thinking of sandblasting for mositure removal. Memory doesn't work well now.

Edited March 9, 2022 by syd

[Alan de Enfield]

43 minutes ago, syd said:

It's more for pulling the moisture out of the steel, I was told. Helps alot with the interior steel ............

 

Are you suggesting that steel is hydroscopic ?

[syd]

Mill scale I think is what I'm thinking of, not sure. Told a long time ago now.

 

That said, I haven't had any of my boats blasted with anything, other than the odd can or stone when cruising through some places.

Edited March 9, 2022 by syd

[john.k]

Mill scale should be removed by the fabricator.....the whole structure should be properly grit blasted......this is dry blasting with steel grit in a blast room with dust collection and grit reclaimers and recyclers.................blasting with low pressure water and a bit of sand /garnet is marginally effective........however ,once the hull has been properly blasted ,it can be high pressure water cleaned to bare metal at a later time...........pressure is 45,000 to 60,000 psi.........and does not remove the "key" left by grit blasting.

[blackrose]

On 09/03/2022 at 15:03, syd said:

It's more for pulling the moisture out of the steel, I was told. Helps alot with the interior steel, wear wise.

 

 

I'm afraid you were told wrong. Sorry to be so direct but that's all nonsense.

[john.k]

Wet sand blasting actually seals water into steel ,into the surface and into any pits ,unless the steel is properly dried after blasting......although there is one way to get around this by using a water based zinc ethyl sulfate binder with zinc powder ........unfortunately ,water sand blasting is not thorough enough to provide a proper surface for inorganic zinc ,and often the zinc comes off in sheets when dry.

[ditchcrawler]

They were just starting to use wet blast on Offshore platforms when I left, They hadn't really taken into account the amount of fresh water required which had to come by boat and stored in tanks, unlike the limitless supply of air for compressing which was also a lot lighter than water.

[syd]

4 hours ago, blackrose said:

 

I'm afraid you were told wrong. Sorry to be so direct but that's all nonsense.

Well we all live and learn, it's what life is about.