Historic Boats for sale online

[MtB]

7 hours ago, davidg said:

Who writes this stuff:

 

Victoria, at a guess!

 

 

[BWM]

1 hour ago, magnetman said:

Just under 3mm? I wonder what that was. Maybe 7/64" ? 

Also I think it was 1/4" not 6mm. 6.35mm. 

 

Maybe they used metric. 

As many people do, I used the nearest metric equivalent. 

[MtB]

Just now, BWM said:

As many people do, I used the nearest metric equivalent. 

 

While others prefer accuracy....

 

 

 

[David Schweizer]

6 hours ago, Dav and Pen said:

I believe that originally The Northwich and Woolwich boats had 3/8th inch ship grade steel bottoms.

Not all of them Pisces, which was a Small Northwich, had a 4" elm bottom.

[DShK]

46 minutes ago, Chris-B said:

We looked at it as well before getting CYPRUS 

Hi Chris, you may have seen but I am the one who bought Cedar. We have at least a couple of mutual friends. Hopefully we can meet one day in the future!

 

Congratulations on purchasing Cyprus, she's a lovely boat 🙂

[Jonny P]

22 minutes ago, MtB said:

 

While others prefer accuracy....

 

 

 

Neither is necessarily accurate given plate thickness are nominal. So converting them isn’t such a big deal providing the calculation is correct.

[magnetman]

I wondered where 'just under 3mm' came from. maybe a UTG ! 

[koukouvagia]

6 hours ago, Paul H said:

But quite sensible if the butty is unattended.  As built, the boats didn’t have “scuppers” or drains from the hatches (“aft cockpit.”). So rainwater goes into the bilges under the cabin.  If you seal the deck/cockpit and introduce scuppers then you’ve got trouble (or wellies!) if you put a  load on!

 

Paul

We had this cover on Hampton for years. When we had work done in 2018 we had a steel deck and drain holes so we don't need the cover now.

 

[magnetman]

One wonders how this issue was dealt with when the boats were intensively used with accomodation space. 

 

 

[springy]

11 minutes ago, magnetman said:

One wonders how this issue was dealt with when the boats were intensively used with accomodation space. 

 

 

 

Mopped or wiped out daily / as required ?

 

springy

[magnetman]

You would not want it coming over the step. It is a small area and I suppose a well done butty cabin will drain forwards. 

 

Still worth having a cover of some sort. 

 

Maybe an early bimini? Lace parasol like they had at Henley could work. 

 

 

 

 

 

 

There would be photos of these. 

[David Mack]

11 hours ago, Dav and Pen said:

I believe that originally The Northwich and Woolwich boats had 3/8th inch ship grade steel bottoms.

 

7 hours ago, BWM said:

The big boats had 6mm sides and baseplate, and the engine room is just under 3mm thick.

 

5 hours ago, magnetman said:

Just under 3mm? I wonder what that was. Maybe 7/64" ? 

Also I think it was 1/4" not 6mm. 6.35mm. 

 

Maybe they used metric. 

 

The Large Woolwich drawing I have (from Laurence Hogg) shows hull side plating to be 1/4" and the bottom plating as 5/16". Engine room casing is 1/8".

[davidg]

8 hours ago, David Mack said:

 

 

 

The Large Woolwich drawing I have (from Laurence Hogg) shows hull side plating to be 1/4" and the bottom plating as 5/16". Engine room casing is 1/8".

 

Is the correct answer. Funnily enough I said the bottom was 5/16" several dozen posts ago but then I've only owned the boat forty odd years so what do I know.

[magnetman]

This is why I was curious of 'just under 3mm' as 1/8 is 3.175mm. 

 

 

[Dav and Pen]

I was going on what we found out when the bottom of Tadworth was replaced in 1977 after 40 years, whatever the 1/16 of an inch would make I don’t know but what was certain was that the steel used was of a much better quality than what replaced it. 40 years later the boat has had its bottom replaced twice by 6mm steel.

Out of interest the Dutch Barge I brought in 2001 was built in 1919 and although there were some patches on it the surveyor found quite a lot of the hull was around 4.7 to 5 mm. I asked him what it would have been originally and he said 5.5 which seemed rather thin to me but the frames were only 450mm apart so plenty of strength. He said the steel was made before 1920 after which steel was made with much more scrap from the First World War and was of much poorer quality.

Edited December 7, 2023 by Dav and Pen
Photo Tadworths old bottom

[BWM]

1 hour ago, magnetman said:

This is why I was curious of 'just under 3mm' as 1/8 is 3.175mm. 

 

 

I was just going on what I was told when Hawkesbury was in Stockton for steelwork and had no reason to doubt it having worked on it myself. 

[magnetman]

I didn't expect this 

 

So as a proportion of its thickness the thinner stuff may be much more variable than the thicker stuff. 

[Stilllearning]

21 hours ago, Dav and Pen said:

I believe that originally The Northwich and Woolwich boats had 3/8th inch ship grade steel bottoms.

So that was 9.525 mm.

[Derek R.]

Imperial measurements are available, and are still understood. Converting from one to the other does not change the thickness, nor does it change the rate of advancing corrosion.

[Jonny P]

22 hours ago, magnetman said:

I didn't expect this 

 

So as a proportion of its thickness the thinner stuff may be much more variable than the thicker stuff. 

That table isn’t the variance to specified thickness. It’s the variance of the thickness within the plate. Because steel plates don’t have uniform thickness.

Tolerances are typically lower values and come in four classifications. The most stringent of which ensures the specified plate will not be thinner than the specified value.

 

[Richard Carter]

2 hours ago, Derek R. said:

Imperial measurements are available, and are still understood. Converting from one to the other does not change the thickness, nor does it change the rate of advancing corrosion.

 

Once I twigged that 1/16" is within 1% of 1.6mm I had an easy thing to remember. So 5/16" = 8mm, etc. etc.

[MtB]

5 minutes ago, Richard Carter said:

 

Once I twigged that 1/16" is within 1% of 1.6mm I had an easy thing to remember. So 5/16" = 8mm, etc. etc.

 

Not only that, but 16swg is also near as dammit 1.6mm, or 1/16'. 

 

 

[Richard Carter]

4 minutes ago, MtB said:

 

Not only that, but 16swg is also near as dammit 1.6mm, or 1/16'. 

 

 

 

That I didn't know. Good stuff. Decimal is fine, but it can't do everything ...

[magnetman]

Just multiply the number of 16ths of an inch you want by 16 and you get the equivalent in millimtres x 10.

 

 

(Approximate equivalent not precise equivalent)

 

Does it work? 12 x 16 is 192 but 3/4 is 19.05mm. Maybe not all that good but reasonable.

 

 

Metres to feet = multiply by three then add ten percent.

 

 

3.2m would be 96+9.6 = 105.6 = 10.5ft approx.

 

 

 

[roland elsdon]

On 07/12/2023 at 09:48, springy said:

 

Mopped or wiped out daily / as required ?

 

springy

No . Didnt matter.composite bottoms on small boats so damp/ wet bilge anyway.

As the butty should be down by the head you have a bilge pump ahead of the cabin bulkhead, in our case it was 2 one each side of the keelson, just in front of the mast.

its academic anyway unless the boat is permanently clothed up.

Steel narrowboats rot from the inside out,  and the outside in . The pitting on some internal hull sides is very evident, on boats that have carried cargo.