Springer Dilemma

[MtB]

Really??!! Phew! There's me thinking that you were all dull, boring, balding old men (except Bizzard)!! Mike, hope the tongue is in the cheek and not elsewhere! Alan, is a cute duck.

 

 

Yes tongue well and truly in cheek. I try to make my klever-dick comments blindingly obviously a p!ss-take* but there is often someone who still takes my posts at face value!!

 

MtB

 

 

*As Alan says, steel doesn't actually leak until it has rusted away to 0.00mm thick. My smart Alec comment was referencing another thread commenting on how surveyors always seem to recommend overplating on boats with hull thicknesses or 4mm. Totally pointless in my opinion as steel of any thickness at all still keeps the water out.

[Delta9]

A surveyor recently told the potential buyers of my friend's boat that over plating is a waste of time because water can get between the plating and the hull, so he never recommends it. Instead he recommended the section be completely removed and replaced. Not surprisingly this put off the buyer and they walked away.

[the barnacle]

 

Ha I did also have my Grandmother's wisdom tooth in a gold fitting on a chain until it got stolen when my parent's house was burgled... And my friend who had to have pins and plates in his arms when he was younger wears one of the plates on a chain too!

 

We are freaks, we will inherit the earth.

cool - shame the tooth was stolen with it having the sentimental value,

[MtB]

A surveyor recently told the potential buyers of my friend's boat that over plating is a waste of time because water can get between the plating and the hull, so he never recommends it. Instead he recommended the section be completely removed and replaced. Not surprisingly this put off the buyer and they walked away.

 

I very much agree with his advice. The technique is called 're-plating'. Over-plating is a monumental bodge in my personal opinion and very often makes no difference to a boat that is already floating and likely to continue doing so for a very long time.

 

MtB

[Water Babe]

I am so glad that I joined this forum. You guys are just so clever. I did not know that 0mm = a leak!! I am learning so much. I will keep on reading your useful posts.

[Paul C]

It's a well known fact that water passes straight through steel plate any less than 4mm thick.

 

 

MtB

 

Very clever.

 

However it misses the point, that its not about static conditions, its about its fitness as a BOAT. If a 6mm hull is struck against a bridgehole or lock mouth, or possibly in a collision with another boat, its going to be less likely to split at a weld than a 4mm or less thickness hull.

[Galeomma]

I am so glad that I joined this forum. You guys are just so clever. I did not know that 0mm = a leak!! I am learning so much. I will keep on reading your useful posts.

I'm sure your tongue is firmly in your cheek with that comment

[MaryP]

My insurance company (Saga) has never asked for any evidence of a survey, let alone insist on a 4mm minimum hull thickness. (Yes, it's fully comp).

Saga would not re insure my boat unless a survey was undertaken, and thereby the boat deemed to be safe. This was because it was 25 years old. i have phoned around, and most boat insurers want a survey at 25 years, or when first insured by them.

[kevinl]

Out of interest how many boats sink from being Springers and made out of recycled gasometers and all the rest and how many sink for other reasons: bad replating, water getting in from above, bad skin fittings or whatever. You can "give a dog a bad name" as they say but is there any actual proof?

How many boats sink from holes below the waterline, not many, it's either fecking up in locks or water getting in from above that sinks boats not the hull thickness.

Insurance companies will eventually reflect risk and historically this has been hull thickness but eventually they will wise up to the fact that thin metal isn't where the big claimers are it's the floating homers and the big claimers that are costing them real money not the possible risk of the maker. The biggest risk should be the contents, on a good day my Springer is worth less than the cost of the kitchen on some boats.

K

[John V]

"Quote Paul C" However it misses the point, that its not about static conditions, its about its fitness as a BOAT. If a 6mm hull is struck against a bridgehole or lock mouth, or possibly in a collision with another boat, its going to be less likely to split at a weld than a 4mm or less thickness hull.

 

That is falling into a trap.........Ok then build it of 25mm plate ......that is as silly an extreme.

 

1mm plate could be used as shell plating for a perfectly adequate boat. It depends on the design and construction techniques and what maintenance level.

 

If the hull is constructed with close spaced, well designed framing then the shell plating only has to withstand the stresses between frames, Yes it may dent, possibly badly but have you ever tried to knock a hole in 1mm steel plate? it is a heck of a lot harder than you might think.!

 

The other way thin steel may be used to construct a good hull is by careful design of the hull shape to maximise steels advantages.

Springers go part way towards this with their Vee hull, this is why they are able to do away with a lot of framing,

Steel built yachts can and are constructed without any framing at all (apart from localised "spreaders to support the mast)

3mm steel is a very common gauge used in yacht construction

 

I think it was MTB mentioned 90' barges constructed out of 6mm steel....I was on a Belgian built ex commercial barge of that aproximate length when it took the ground as the tide went out, looking along the main corridor it was quite alarming to see the twist. (it took up again fine when the tide came back in)

When I asked about construction I was told it was built of 5mm plate..

 

With the simple box shaped hull of the average narrowboat a thicker plate is probably required due both to the shape and the very basic framing used by most builders.

The 6' 5" wide box shape is not ideally shaped to use the benefits of steel to it's best advantages. It is however easy to build and maximises internal volume for a given hull length.

 

It seems to me that the problem with Springers is that people compare them directly to other types of narrowboat and this can be misleading as Springers are a more sophisticated hull

 

Very clever.

 

However it misses the point, that its not about static conditions, its about its fitness as a BOAT. If a 6mm hull is struck against a bridgehole or lock mouth, or possibly in a collision with another boat, its going to be less likely to split at a weld than a 4mm or less thickness hull.

 

 

Sorry this quote was meant to be at the top of the page ....not the bottom..Doh!

Edited October 12, 2014 by John V

[Paul C]

"Quote Paul C" However it misses the point, that its not about static conditions, its about its fitness as a BOAT. If a 6mm hull is struck against a bridgehole or lock mouth, or possibly in a collision with another boat, its going to be less likely to split at a weld than a 4mm or less thickness hull.

 

That is falling into a trap.........Ok then build it of 25mm plate ......that is as silly an extreme.

 

1mm plate could be used as shell plating for a perfectly adequate boat. It depends on the design and construction techniques and what maintenance level.

 

If the hull is constructed with close spaced, well designed framing then the shell plating only has to withstand the stresses between frames, Yes it may dent, possibly badly but have you ever tried to knock a hole in 1mm steel plate? it is a heck of a lot harder than you might think.!

 

The other way thin steel may be used to construct a good hull is by careful design of the hull shape to maximise steels advantages.

Springers go part way towards this with their Vee hull, this is why they are able to do away with a lot of framing,

Steel built yachts can and are constructed without any framing at all (apart from localised "spreaders to support the mast)

3mm steel is a very common gauge used in yacht construction

 

I think it was MTB mentioned 90' barges constructed out of 6mm steel....I was on a Belgian built ex commercial barge of that aproximate length when it took the ground as the tide went out, looking along the main corridor it was quite alarming to see the twist. (it took up again fine when the tide came back in)

When I asked about construction I was told it was built of 5mm plate..

 

With the simple box shaped hull of the average narrowboat a thicker plate is probably required due both to the shape and the very basic framing used by most builders.

The 6' 5" wide box shape is not ideally shaped to use the benefits of steel to it's best advantages. It is however easy to build and maximises internal volume for a given hull length.

 

It seems to me that the problem with Springers is that people compare them directly to other types of narrowboat and this can be misleading as Springers are a more sophisticated hull

 

 

Sorry this quote was meant to be at the top of the page ....not the bottom..Doh!

 

Good points, yes its true that strength in construction is a result of many factors, one of them being material thickness. Canal boats are generally tougher construction than seagoing because they're likely to encounter many more locks in their lifetime, so be cautious when making comparisons here.

Edited October 12, 2014 by Paul C

[alan_fincher]

My insurance company (Saga) has never asked for any evidence of a survey, let alone insist on a 4mm minimum hull thickness. (Yes, it's fully comp).

 

 

Saga would not re insure my boat unless a survey was undertaken, and thereby the boat deemed to be safe. This was because it was 25 years old. i have phoned around, and most boat insurers want a survey at 25 years, or when first insured by them.

There has been some argument about this in the past, specifically in respect of Saga.

 

What I believe the situation to be is that once you are insured with them, they say they will not ask you for surveys in order to continue cover.

 

But I believe Mary is correct that if you actually went to them with a 25 year old boat, and no recent survey, then they probably would not.

 

I suppose I could try it for my 78 year old boat, but I can't see them granting it, somehow!

[John V]

 

Good points, yes its true that strength in construction is a result of many factors, one of them being material thickness. Canal boats are generally tougher construction than seagoing because they're likely to encounter many more locks in their lifetime, so be cautious when making comparisons here.

 

 

True...but many of the denting problems associated with canals are to the upper works and to the "cheeks" of the bow and they might need heavy rubbing bands/stiffeners or to be of thicker gauge to resist denting but it seems simplistic just to build it all in heavy plate

 

Mostly the risk for denting on yachts is on the bottom or on the bilges from taking the ground. This is often countered by using poured concrete ballast.

[Bee]

There are plenty of steel cruisers built from 4mm steel and some of them are very expensive. Thick steel is great for resisting collisions with stonework and other boats etc. but its real value for narrowboats is that it takes longer to rust through. If you keep it painted on the outside and dry on the inside 4mm is fine (and yes that does include painting the underneath)

[FadeToScarlet]

True...but many of the denting problems associated with canals are to the upper works and to the "cheeks" of the bow and they might need heavy rubbing bands/stiffeners or to be of thicker gauge to resist denting but it seems simplistic just to build it all in heavy plate

 

Mostly the risk for denting on yachts is on the bottom or on the bilges from taking the ground. This is often countered by using poured concrete ballast.

My boat is built from 1/4" wrought iron, with iron knees every 3' or so and a keelson, and it's still very, very dented around the fore end and stern end, and the sides are corrugated in between the knees.

 

I like it, though, it adds character.

[Sabcat]

 

I very much agree with his advice. The technique is called 're-plating'. Over-plating is a monumental bodge in my personal opinion and very often makes no difference to a boat that is already floating and likely to continue doing so for a very long time.

 

MtB

 

I halfway agree with this. If the overplate is welded properly it does make a difference, if it isn't it's arguably worse than doing nothing. It doesn't have to look terrible, waterline pitting that's not wide can be sorted by having a strake welded the length of the boat, as long as it's sealed all the way around, job done. Same with over plating a bottom, do it all, weld it all the way around and cut holes in the in the middle of the old bottom and weld it to the new plate to stop sagging and it's good.

 

Plates randomly welded over thin bits looks horrendous no matter if they're done properly or not. In that sense cutting out and letting new plates in is always better and undoubtedly the right way to do it.

 

On the subject of Springers there's one here that was stretched a few years ago on a limited budget (to the point that it's got a split level cabin part fibreglass part steel) which had nothing at all in the way of maintenance for many, many years. There were concerns about whether it would survive being craned out but beyond some minor pitting on the waterline it's hull was sound.

[John V]

My boat is built from 1/4" wrought iron, with iron knees every 3' or so and a keelson, and it's still very, very dented around the fore end and stern end, and the sides are corrugated in between the knees.

 

I like it, though, it adds character.

 

I am not a metalurgist but isn't iron more malleable than steel ?

 

whatever, it is unlikely that any modern cruising boats will have as hard or as long a life!!!

 

 

 

 

I halfway agree with this. If the overplate is welded properly it does make a difference, if it isn't it's arguably worse than doing nothing. It doesn't have to look terrible, waterline pitting that's not wide can be sorted by having a strake welded the length of the boat, as long as it's sealed all the way around, job done. Same with over plating a bottom, do it all, weld it all the way around and cut holes in the in the middle of the old bottom and weld it to the new plate to stop sagging and it's good.

 

Plates randomly welded over thin bits looks horrendous no matter if they're done properly or not. In that sense cutting out and letting new plates in is always better and undoubtedly the right way to do it.

 

On the subject of Springers there's one here that was stretched a few years ago on a limited budget (to the point that it's got a split level cabin part fibreglass part steel) which had nothing at all in the way of maintenance for many, many years. There were concerns about whether it would survive being craned out but beyond some minor pitting on the waterline it's hull was sound.

 

I agree with Sabcat on this. Good quality doubling is fine if it is done correctly the holes cut along the centre of a plate and then welded through are very important. This is something that may get skimped because of the problems of access in a fitted out boat. It is not as good a solution as cut out and replace, which if done properly is as good as the original build.

 

It is vital with doubling that the welds are really good. It is also vital that there is no way wet can get from the inside of the old hull into the gap. If this happens the rust forming produces so much pressure the plate can be forced off.

 

If you are going to have any significant area doubled you need to be able to trust the steelworkers completely.

[MtB]

 

It is vital with doubling that the welds are really good. It is also vital that there is no way wet can get from the inside of the old hull into the gap. If this happens the rust forming produces so much pressure the plate can be forced off.

 

If you are going to have any significant area doubled you need to be able to trust the steelworkers completely.

 

Exactly. And how will you know if the welds are 'really good' and there is no way for wet to get inside into the gap? Other than by waiting for a few years to see if the boat still sinks?

 

This is why I am so critical of overplating. It might look good but there is no easy way to tell for sure.

 

MtB

[Sabcat]

It's a bit like any other work on a boat - use someone that's good. Don't tell them how to do the job, tell them the problem and ask them what the job is. Best way to approach any job in any circumstances where you're not an expert I reckon. The trick is finding someone that's good.

[John V]

I have some large areas of Sabina overplated (now about 20 years ago) and yes I did trust the welder and plater totally. The welder (unfortunately no longer with us) was a coded and very experienced ships welder who was fastidious in his work (the weaves on his verticals look like machine embossing)

 

I think it is fair to state though, I would be very cagey about having anyone else do such work

[mikevye]

Many thanks for ALL your responses (no honestly!). On a further positive note I have found the

original sales brochure stating that 26' springers were 1/8th plate at the TIME of construction

and longer boats were 3/16th. So it would appear that the surveyor on insisting that a min of 4mm

was required actually wanted the boat to have more steel thickness than when it was new!!!