Double Plating Question

Hi no way you must cut away all bad plates weld in to gather in the proper way.
have replaced 20m2 of the botton of our boat shall put some pic of my project so you can see how to do it the right way
bestregards Erik

WOW! are you sure you want to undertake a project like this?????maybe the hull isn't as bad as it looks in the pics, but WOW!!!...i agree...cutting out the bad is the only way to go...otherwise, rust will just fester under the patch like cancer...Tim

Hi Yes that the way you should do it we veld first on the inside then on the outside.Im gong to put in some pic from my job so you can see more my english is not so good.
Erik

Please size them so they don't screw up the whole thread!

That image was ridiculous. Do we really need a 2400 pixel wide image? The image has been reduced. Please keep images under 640 pixels in width.

Hi,

Is the hull rotten on both sides here or just the one and is this all of the holes you have or just a sample?

I guess your idea of "looks pretty good" and mine are different. IMO you have a good bit of metal to remove and replace. You'd be wise to invest in a plasma cutter and a magnetic straight edge to run it against. Not that big of a job really if you have the right tools. Weld from the inside first, grind the weld in the seam even from the outside and then weld the outside. If you have the right equipment you're looking at 4 days work to do it right. Remember, no corners where plate meets patch, always use as large of a radius as you can fit.

Hi,

Henning - The original poster has already stated that he has a fabricator ready to to the metal work, do you think it makes better sense to buy some tools and carry out a procedure the poster might have no experience of at all?

You could also do with refreshing your Class rules welding techniques a bit, the mega radius is not the current practice (in GL and LROS anyway).

I discovered this point when arguing about the way an insert plate was installed in a new build.

Hmmm... I guess the new way will make it down to the Lloyds office here in Aus in a couple of years, because they just made me do radiuses on some plate patches... BTW, it sounded to me like he had somebody lined up who would weld fresh metal over his rotten stuff hence the "Double plating" question. I'd hesitate to call them a fabricator much less a shipwright.....

And yeah, I think taking on a boat like this is a perfect time to learn to weld and fabricate metal. It's fun, it's not rocket surgery either. With a MIG welder most people can learn to run a structurally sound and sealed weld in under a couple of hours. I enjoy it anyway...for a bit... then it's like work That boat will see plenty of need for welding.

Greetings,
My opinion is: Go with a proper repair (cut and replace) rather than band-aid solutions.
Peter

Crazy? No, there's a bunch of ways to take care of this, but the right way is to cut away the rotten metal back to good (from your pictures I'd cut it up to that first seam) and insert a new plate and flush weld it in. That is the proper way of replacing metal. Heck, you could just get a tub of Belzona and trowl it on and fair it. It would most likely last several years with no issues. It wouldn't be right though. At the end of the day, it's your boat. I've fixed this kind of stuff various different ways, as long as the boat isn't in class, there's nobody to object to it. If it were in class, the surveyor would tell you to cut it back and put in a new plate. I have also seen people sand blast the pits, fill them with a Mig welder, grind them flush and paint before the surveyor shows up. It's up to you to decide how you want this project to go.

To anyone who is familiar with metal fabrication, it should be a pretty straightforward task. Cut out the bad (plasma preferably, and hopefully not a torch) and replace with new. (MIG or TIG ideally) Cut back far enough into good material, and replace.

There are always many ways to do something. On that same note, there is always the right way to do it.

For the time and effort, you have the comfort knowing it was done right at the end of the day.

That's good, it really isn't as big of a deal to do right as you think, You can rent plasma cutters, and long magnetic straight edges are available at most industrial and machine supply shops. You just set the straight edge so when you run the torch end along it it cuts just about 1mm proud of where yo want it. That will put the rough pits in the cut on the line and when you grind smooth it'll be on the line. You need a 4" angle grinder with an assortment of cut off and grinding discs. (buy a box of thin ones) Get the flapper wheel discs for sanding stuff, they last way longer than flat ones. Your plates look pretty flat with no compound curves, so forming them into place should be straight forward. Then just Mig it together. Like I said before, with the right equipment, you've got a 4 day job. A pro crew could do it in a day and a half.

Looking for information on obtaining ultrasonic tester for steel hull

Hello YachtForums community,

I am very new to this community and this is my first post. I have an opportunity to get 57' Roamer. It is located in an offbeat location where the nearest capable surveyor is mile$ (and hundred$) away.

I am very familiar with "frozen snot" hulls, having owned a few for a couple of decades, but steel hull is a totally new material for me.

I'd like to get some information on obtaining (buying, or renting) an ultrasonic hull tester and would love to get any advise on checking a hull condition on 1965 vintage (other than sounding).

Thank you for reading my post,

Traveler.