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Steel vs grp


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#1 Chrisc

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Posted 08 March 2018 - 08:21 AM

This is an 'opinions sought question.
In our search for a European canal boat the available hull material options are steel 95% and grip 5%.
In NZ everybody knows and is comfortable with grip and in Holland the same is true for steel and the Dutch have been building steel boats for decades and know what they're about.
However, grip is more prone to osmosis in fresh water, but then it is said that steel boats die from the inside out.
What we have seen on the typical 12m Dutch steel motorboats is that they go crazy with lining the interior and so to inspect the internal steel structure would require quite some dismantling. But then the surveyors have an ultrasound device with which they can determine plate thickness. We have heard that the Dutch boaties schedule an external blast and repaint every 10 years at 1000 euros per metre.
Since we would be planning a six months on the boat, six months at home the opportunity to quickly nip down to the boat for a bit of maintenance is not there.
I dunno what hull material to go for.
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#2 Island Time

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Posted 08 March 2018 - 08:29 AM

I'd do GRP if given the option. Osmosis wont sink you. I've seen steel boats completely rusted away, till they sink.


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#3 Fish

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Posted 08 March 2018 - 08:49 AM

Rust never sleeps.
Bernard Moitisier was a big fan of steel, building the boat he went on to 'become famous' in by sailing non stop from Tahiti to France via Cape Horn.
He raved about how strong it was and how dry, in the Southern Ocean, in comparison to a wooden boat with leaks.
He learnt the maintenance of steel (painting) by crewing a passage on a freighter.

However, with his next boat, he still made it of steel, but made ALL interior joinery fully removable, so he could inspect and paint the interior. He had issues with rust in the places behind the joinery on his first steel boat...

For living aboard, the big problem with steel is the coldness and condensation, hence, as you say, how all those boats are lined. Good lining makes them warm and comfortable, however it is entirely exclusive to inspecting and painting the interior.

That said, they locals must know how to deal with this issue. There is a lot of strength in the old saying, 'when in Rome'
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#4 John B

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Posted 08 March 2018 - 09:21 AM

I know that in the English canals we'd groan if we happened to have a GRP cruiser in front of us or coming in with us  for the locks. The steel boats you just go in and lean against whatever. GRP its all fenders and running around with springs  and general panic stations.

 So there is that factor.


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#5 twisty

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Posted 08 March 2018 - 10:32 AM

There's a reason why most canal boats are steel. My (limited) experience on the canals is that I would only consider steel now. It can be like dodgems at times. In the Netherlands there is literally thousands of boats 100 years old so I don't think rust is the problem it would be here in salt water.


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#6 Steve Pope

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Posted 08 March 2018 - 10:52 AM

Ultra sound testing will give you hull thickness, (removable) insulation down to the waterline, which all boats on offer would already have will cover the moisture issues. Correctly sourced and sprayed on insulation will do the same. Any surveyor in Holland worth his salt will know all the spots on canal type boats that will potentially be liable to water entrapment / rust problems. To me steel is a no brainer. Of course if you add ally to the mix, I could / perhaps would change my mind. The shear numbers of metal boats available against plastic ones should be a give away.  Good Luck!


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#7 John B

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Posted 08 March 2018 - 10:56 AM

Slightly off track, friends of ours were getting frustrated with the continual maintenance of steel on their cruising boat, it was wearing them out.

 Until they got T boned at anchor in sept by a catamaran doing 8 knots into the anchorage, other side of musket .

 

 they like steel now.


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#8 Aleana

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Posted 08 March 2018 - 11:02 AM

Aluminium?


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#9 wheels

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Posted 08 March 2018 - 11:40 AM

Osmosis is only a worry for hulls built back in the 70's 80's of Pure polyester re3sin. the modern day Ester resins are Vinyl ester and that does not cause a problem. If Osmosis is present, it is nothing like the old scare mongering stories years ago of hull falling to bits. It is simple blisters that can be burst, dried and filled. No need for expensive hull planing and so on.

Every material has a plus and minus.

Ferro is the only perfect material ;-) ;-)

 


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#10 Chrisc

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Posted 08 March 2018 - 12:44 PM

Thanks for the replies - have to make our minds up as we are flying out pretty soon.
Now back to CEVNI study. It a licence needed to operate a vessel on the waterways. Studying lights at the moment. One yellow light indicates two way traffic - two yellow lights indicate one way traffic. Makes sense to the French, I suppose.
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