First narrowboat survey , what would you expect on a 10 year old hull

[notts_alan]

As the title says , I am moving on from my cruiser and buying a wide beam Liverpool built boat.

I have never had a survey on any GRP boat I owned.

Because of the cost involved I have opted for a survey , just wondering what you would expect wear wise from a 10 year old hull ? At what size mm thickness would you walk away from?

Cheers

 

Alan

[Robbo]

I wouldn't expect any to be honest.

[Paul C]

Impossible to say. Its not just about the overall thickness, its also important to consider corrosion and weld quality in critical areas.

[Alan de Enfield]

You are asking a question that is impossible to answer - just taking one aspect of your question :

 

"...just wondering what you would expect wear wise from a 10 year old hull...."

 

The answer is "it depends"

 

If it has been moored in a marina, if it has had a mains-hook-up connected for long periods, if it has no isolation system,if the marina has 'leaky electricity' then a brand new hull COULD be holed/perforated within 12 months.

 

If it has ben CCed,never hooked up to mains, been blacked every year, scratches touched up when occurred and generally looked after it could have as much as 99.99% of its original thickness left after 20,30 or 50 years.

 

Your survey is NOT a pass or fail test, it is purely a condition report (which hopefully your surveyor will do correctly), it is up to you to interperate the survey as to if the boat meets your expectations and is value for money.

[notts_alan]

Cheers lads , yes a pretty impossible question with a lot of variables , never been in a marina on mains.

I will hope for a good survey and keep my fingers crossed .

If it is say 5 mm from a original 10 mm at ten years old would you consider it pretty worn for the age ?

[Chewbacka]

Cheers lads , yes a pretty impossible question with a lot of variables , never been in a marina on mains.

I will hope for a good survey and keep my fingers crossed .

If it is say 5 mm from a original 10 mm at ten years old would you consider it pretty worn for the age ?

In a sense it does not matter if it is good for it's age or not as if you look after it there will be little further corrosion.

So the question is, how thin a boat would you want to buy?

What is important though is corrosion is often not uniform and often pitted so if a surveyor says it was 10mm but is now 5mm ask him is that worst case or average? If average the corrosion could have resulted in steel with a thickness varying between a few mm thick and more than 5mm.

There may be pitting which is almost all the way through.

 

So discuss the results with the surveyor and decide if you want it as is, or if it needs overplating or just walk away.

[Bee]

10 years, COULD be all sorts but most likely to have some visible pitting on the sides which could be halted with some paint and a mucky mess underneath that if pressure washed will show many shallow pits that could be halted with paint. The thing is that paint is important and if you get the boat lifted out then lie under it you will be shocked at just how big the thing is. I'd be quite happy with shallow pits, 1-2 mm or so because I would get it painted every 2-3 years, maybe 4 years with a really good epoxy. So far as resale is concerned a pile of receipts for docking every 3-4 years and proof that the bottom has been done would keep me interested, without that I would not be impressed.This adds a lot onto your budget but that's the way it is. I would be v. surprised if any of the steel is wasted enough to need repair but it can happen.

[alan_fincher]

For a 10 year old boat I'd be very disappointed if there was 1mm lost over any significant area let alone 5mm.

 

I'd maybe accept small numbers of pits greater than 1mm, but not much greater than 1mm.

 

We sold a boat twice that age relatively recently, and we were told that almost no wastage had been found, and certainly none of the 20 year old steel was down by as much as a millimetre, I believe.

[Robbo]

Cheers lads , yes a pretty impossible question with a lot of variables , never been in a marina on mains.

I will hope for a good survey and keep my fingers crossed .

If it is say 5 mm from a original 10 mm at ten years old would you consider it pretty worn for the age ?

When getting the survey done, be there. The surveyor should go around all the issues with you and this is worth more than the bits of paper s/he produces to wether it's a good boat or not.

[Judgejim64]

I had my 2004 Liverpool boat surveyed last year and had lost 0.8mm in one small pit but overall the average loss was miminal.

[Bill]

One thing to be aware of LBs about that age. The steel often has not had the mill scale (hard deposits formed in the milling process) removed, removal was an optional extra which most people (me included) did not opt for. For the first few years this seems to stay hard and stuck to the plating. Over time this will de-laminate in chunks and look like the steel is corroding (it isn't), The gas locker and engine bilge seem to be the first to go, a session with a heavy duty scraper and you will be back to the proper plate which in all likleyhood will be unmarked.

[notts_alan]

Thanks for the replies , gives me a better understanding , I will be there when lifted and surveyed and use my own eyes as well.

Its a one owner from new and all paperwork for regular maintenance / blackening is present , it was sat on a canal in middle of no where with no marina hook up , engine and solar for power.

[canals are us?]

I have a 1998 Liverpool trad narrowboat and the survey 3 years ago when I purchased it showed the 10mm baseplate thinnest was 9.6mm and the 6mm sides 5.8mm in places, The swim if I have the right terminology was done in 6mm and was 5.9mm. The deepest pit was 1.1mm. The surveyor said "if you don't buy it, I will"!!

So in the younger boat I would expect very little loss.

James

[matty40s]

dont forget, you get far more corrosion on the 6mm waterline than on the 10mm baseplate..

[dmr]

dont forget, you get far more corrosion on the 6mm waterline than on the 10mm baseplate..

 

Not convinced about this even though it is accepted wisdom. As long as the boat is looked after (regularly blacked) then I suspect the bottom and lower sides corrode most. Many overplating jobs are the bottom and bottom foot of the sides rather than the waterline.

However last night the boat moored opposite looked pretty rough on the waterline.

 

By co-incidence I had a quick look at our baseplate yesterday, (2001 boat), it looked pretty good but quite a bit of pitting, did not measure this as the dry dock floor was cold and wet and time was running out, but I reckon 1.5 mm. Think we will maybe get craned out next time (when the boat is 20) and have a better look and maybe epoxy the bottom.

 

...............Dave

[Neil2]

 

Not convinced about this even though it is accepted wisdom. As long as the boat is looked after (regularly blacked) then I suspect the bottom and lower sides corrode most. Many overplating jobs are the bottom and bottom foot of the sides rather than the waterline.

However last night the boat moored opposite looked pretty rough on the waterline.

 

By co-incidence I had a quick look at our baseplate yesterday, (2001 boat), it looked pretty good but quite a bit of pitting, did not measure this as the dry dock floor was cold and wet and time was running out, but I reckon 1.5 mm. Think we will maybe get craned out next time (when the boat is 20) and have a better look and maybe epoxy the bottom.

 

...............Dave

 

Absolutely right.

 

It is indeed accepted wisdom that boats are more likely to rust at the waterline but it isn't true. It goes hand in hand with the nonsense about baseplates not rusting owing to lack of dissolved oxygen.

 

The fact is most people have no idea what state their hull is in, and surveyors can only give an educated opinion. You need to blast the thing back to bare metal and if you do, you will find most of the pitting (if there is any) will be on the baseplate and the lower hull sides.

 

As to the OP question, I wouldn't expect to find anything measurable on a 10 year old hull if it has been properly looked after. If the surveyor finds any pitting at all and you still fancy the boat, include the cost of grit blasting and proper hull protection in your (revised) offer.

[dmr]

 

Absolutely right.

 

It is indeed accepted wisdom that boats are more likely to rust at the waterline but it isn't true. It goes hand in hand with the nonsense about baseplates not rusting owing to lack of dissolved oxygen.

 

The fact is most people have no idea what state their hull is in, and surveyors can only give an educated opinion. You need to blast the thing back to bare metal and if you do, you will find most of the pitting (if there is any) will be on the baseplate and the lower hull sides.

 

As to the OP question, I wouldn't expect to find anything measurable on a 10 year old hull if it has been properly looked after. If the surveyor finds any pitting at all and you still fancy the boat, include the cost of grit blasting and proper hull protection in your (revised) offer.

 

We were talking about this in bed this morning (I assume all boaters talk about corrosion and oxygen levels in bed in the morning???)

The canal water gets a lot of movement, boats stir it up and lock emptying really moves the water about, so I would think that in many places and for much of the time there is almost as much oxygen 3 foot down as there is a few inches down. Probably a bit different in a quiet marina in winter but I would love to see some facts on oxygen vs depth.

I think not "blacking the bottom" is because its difficult and unpleasant work, and just not viable in many dry docks.

Is this not why builders use thicker and thicker baseplates?

I also suspect that there is significant rusting from the inside out at the bottom inch or two of the sides on most older boats.

We have never blacked the bottom but like I said, probably will next time. Question is what is best to use? Main objection is to fill the pits so I reckon an epoxy but maybe not to hard, scrapes will certainly takes some epoxy off but don't want it to tear out of the pits.

 

We just came out of the water after three years to have a look at the state of the hull with two pack on. All very interesting.

 

................Dave

[Bee]

I think the last 3 posts, 2 from DMR and one from neil2 are spot on. The only thing I would say is that on the Canal du Centre (?) in France there are many sections of old sheet piling that have corroded right through roughly at the waterline leaving just about intact metal above and below so maybe there is a bit of a waterline effect, mind you the rest of the piling is pretty much scrap so in reality the best thing to do is paint everything that gets wet.

[MtB]

I think the view that there is no oxygen in the water two feet down is demonstrably false.

 

If there was no oxygen I suggest there would be no fish or other aquatic life down there two feet under either.

[churchward]

For a 10 year old boat I'd be very disappointed if there was 1mm lost over any significant area let alone 5mm.

 

I'd maybe accept small numbers of pits greater than 1mm, but not much greater than 1mm.

 

We sold a boat twice that age relatively recently, and we were told that almost no wastage had been found, and certainly none of the 20 year old steel was down by as much as a millimetre, I believe.

I agree. Our boat which was about 15 years old when we had it surveyed before purchase nowhere was found to be thinning more than 0.3mm and most places less than that but a few pits a bit more.

 

Not had a survey since but the condition at each blacking has looked very good so I don't expect to have lost much more in the last 6 years. I assume at some point the insurance company will require another survey.

 

We have kept the boat mostly in marinas but I only connect to the mains if we stay on the boat in the marina to service it or do other work.

[churchward]

I think the view that there is no oxygen in the water two feet down is demonstrably false.

 

If there was no oxygen I suggest there would be no fish or other aquatic life down there two feet under either.

Quite. It is true though that less dissolved oxygen is found at depth. I think the water line thing comes from the fact that at the water line the water is lapping so the waterline goes from being in water then in the air but wet.

[notts_alan]

Survey results were great , good solid readings and not a lot lost , still 10mm in places 9.9 /9.8 in others...sides 5.7/5.8.....so very happy with the results , plenty of years left in her for me...

Thanks for the replies..alan

[Guest]

Survey results were great , good solid readings and not a lot lost , still 10mm in places 9.9 /9.8 in others...sides 5.7/5.8.....so very happy with the results , plenty of years left in her for me...

Thanks for the replies..alan

Great news

Edited August 29, 2016 by Guest

[peterboat]

Good news indeed now black it before putting it back in!

[Greylady2]

Good news peter :-)

 

Enjoy