Old steel boat - are riveted hulls any good and what lies ahead?

[Timber wolf]

Hi everybody Im thinking of buying an old steel boat we think year of construction 1945ish. The hull is a riveted steel hull motor boat twin screw may be ex military.I would like to know are riveted hulls any good age being taken into account and what might lie ahead for me when and if I shot blast the steel back to bare metal. Thanks

[gonzo]

Riveted hulls can last for a long time. You need a surveyor with good knowledge of that type of construction to inspect it. There is no way to tell you over the internet whether it is a good or bad boat.

[PAR]

If this boat has been in the water this whole time, the hull plating has been changed or will likely need to be changed. I can't imagine any designer specing out plating scantlings, intended to tolerate corrosion for over a half a century. In other words, if the design parameters are typical, then at least 50% of the plating thickness has been eaten away by corrosion by now, if it hasn't been replaced.

[Frosty]

Titanic was riveted --and built in Ireland, where is it now--just sayin.

[PAR]

Nothing wrong with riveted boats, but get the old lady surveyed or you could just be buying a bucket of rust.

[Landlubber]

..... my old boat (160 footer) was riveted. She was made in Germany 1957, and as at 1982 was in new condition (as per build spec). We did ultrasound reading extensively over the hull, she was 12mm all over, very few places showed any deterioration at all.
....every boat is different....how well they have been cared for is the most important.
it is quite easy to determine just how good they are from both visual and ultrasound readings. The rivets are certainly capable of being rehammered if necessary, but I doubt it.

[Poida]

Couldn't the hull be welded?

[Frosty]

Yes I have seen riveted/ welded hulls.

[MikeJohns]

I've been involved with several old steel riveted vessels.
Of particular interest to you, two months ago we patched up a 1908 vessel. The year before a 1935 one.

Some of the overlaps had bulged and were packed with rust and popped rivets. We did all the repairs with welding. The damage to both hulls was very localised to wet areas. Most of the non corroded plating on both those ancient hulls was so close to original thickness as to be in it's original condition.

Welding and riveting overlapped for decades.
There are moderate sized ships and deep sea trawlers built even into the 60's in German yards that had welded butts and riveted seams. Riveting is very robust and immensely strong and largely immune from fatigue issues related to weld shrinkage and locked up stresses. There's so many backing and overlapping plates that smaller hulls end up being incredibly tough even tougher than an equivalent scantling welded hull.

So if you can find one in good condition don't hesitate. If you want any advice you are welcome to email me.

The picture is of the 100+ year old vessel, a concreted base in the chain locker was the culprit here but the adjacent plate is pristine in thickness. It was a quick and easy repair.

[ACuttle]

Originally Posted by Timber wolf

Hi everybody Im thinking of buying an old steel boat we think year of construction 1945ish. The hull is a riveted steel hull motor boat twin screw may be ex military.I would like to know are riveted hulls any good age being taken into account and what might lie ahead for me when and if I shot blast the steel back to bare metal. Thanks

Do you have any photo's of this boat? I have a feeling I might have done some work on her a few year back - just the way you've descride things.

[MikeJohns]

Originally Posted by Landlubber

..... my old boat (160 footer) was riveted. She was made in Germany 1957, and as at 1982 was in new condition (as per build spec). We did ultrasound reading extensively over the hull, she was 12mm all over, very few places showed any deterioration at all.
....every boat is different....how well they have been cared for is the most important.
it is quite easy to determine just how good they are from both visual and ultrasound readings. The rivets are certainly capable of being rehammered if necessary, but I doubt it.

Yes care is everything, nothing need corrode if its kept painted and the anodes are kept up and the bilges kept dry there's no reason the vessel won't last literally hundreds of years.

You can also gouge around a loose rivet and weld it up.

John Is that ex boat of yours in Brisbane ?

[Frosty]

Is welding straight forward or do you need special rods.

[Landlubber]

Mike,

No, my old girl was bought in Noumea in late 1981, she was the Moana. (Carmen).
I delivered her to Fiji for the new ownerslater and she traded from there. I do not know where she is now.
I was also Engineer on my Mums boat Skode (Brisbane) another riveted vessel, but the corrupt government and associates at the time made it impossible for us to work her from Brisbane, and she was lost......very sad and interesting case, that I would deeply like to know more about.
WE WAS ROBBED..as they say.

[MikeJohns]

Originally Posted by Frosty

Is welding straight forward or do you need special rods.

We cut bits out and have them tested, so far all the supposed Iron hulls were actually low grade steel (even one built in 1880). So welding was pretty simple and was done with whatever the class societies were happy with. Filler rods that tolerate impurites are good, there's often a lot of white lead in resin binders coating old riveted hulls and between overlaps so 'washing' with an oxy torch can be a good process before final welding.

[MikeJohns]

Originally Posted by Landlubber

........
WE WAS ROBBED..as they say.

Sorry to hear it John, you can't fight a corrupt bureaucracy with much success. Sounds like you could write a good book with some nice pictures at any rate !