Kedian Engineering Overplating [pics]

[madcat]

It does make you think about how good some surveyors are. I've heard a few stories over the years which I'm not repeating on here.

[Neil2]

It's worth reminding any newcomers to the game that might be following this that, just like anyone can call themselves a plumber of carpenter, anyone can call themselves a marine surveyor.

 

I'd say it was about time the RYA or CRT or whoever introduced a status equivalent to a "chartered" surveyor except I have no faith in building surveyors so qualified.

[Martin Kedian]

I have gone along with numerous potential buyers of boats as an engineer to see if they are worth paying for a survey prior to purchase often it is quite simple to determine a survey is a wast of money

[Bloomsberry]

That's a good question. You would think that if the gap between the plates is truly airtight, once all the oxygen in the trapped air had been used up the rusting process would stop. This is why there's a common belief that stationary boats in stationary water don't rust as fast as a moving boat where the supply of oxygen is constantly being replenished.

 

But it isn't that simple. As I understand it boats that are constantly on the move are more likely to rust evenly whereas boats that spend most of their life tied up are much more prone to pitting. I don't fully understand the science behind this but I think it is fact. So I'm tempted to think that the same might apply to an overplated boat where the air inside provides a limited supply of oxygen but it might well be enough to work on a small area, form a pit and eventually perforate the plating.

 

As a matter of interest I've just recovered a couple of 3mm mild steel offcuts which have been buried at the back of the garage for several years. Parts of the surface are unblemished but other parts have quite deep sections of localised rust. It's hardly a scientific analysis but this does tend to support the above theory.

 

Another thing to consider is that the overplating will make the boat heavier and so will sit deeper in the water.

 

This as a consequence should raise the waterline up the hull sides a certain distance above the previous waterline.

 

As the majority of corrosion occurs here then the new section of hull exposed to the waterline will have previously been above the waterline and in better condition ?

 

Just a theory, it all depends on how much lower the boat sits in the water of course.

 

Edit - this refers to the original hull behind the overplating

Edited January 30, 2015 by Bloomsberry

[Martin Kedian]

That's true about the boat sitting lower in the water you can remove some ballast if needed We usualy recommend that the new plates go up above the new waterline but take your point about the waterline being suspect

[Bloomsberry]

Also a good way of discovering if overplating has water between the plates is when in dry dock, pay great attention to all welded seams when the boat is first out of the water. If there are damp patches that dont just dry up like the plate sides then this is a possible breach in the weld and could do with investigation.

When my overplated boat came out of the water last year there was a jet of water coming from behind the plates, a bit of a giveaway really !

[Martin Kedian]

There as many poorly built shells as thee are poorly done over plates a good welder ensures new boats are watertight there is no difference in ensuring that water remains on the outside of the over plating the skill required is the same

[Bob the welder]

That's looking good .bob the welder

[Bee]

I would be happy with an overplated boat, with a few extra checks but I would be worried if the original plating was rusted to nothing, like the sills of a car, I would be worried about water getting between the plates from the inside. If the plating, original as well as doubling, is rusting from the inside as well as the outside this is a Bad Thing. Having said that though, if the original plating is good for 20 years plus, the overplating for 15 years plus then that is pretty good and then it can be replated and start all over again.

Edited February 2, 2015 by Bee

[Martin Kedian]

Thanks Bob much appreciated

[sanctuary79]

Just to echo as a few other here, I too have had very positive experiences when dealing with Kedian Engineering.

Recommended for quality of work and communications.

A.

[Martin Kedian]

Many thanks Sanctuary for your positive comments Martin

[Mitchellmoxo]

the finished project:

 

[Sabcat]

Looks excellent.

[kris88]

Yea good job

Regards kris

Edited February 13, 2015 by kris88

[cuthound]

Does the new epoxy blacking go all the way to the blue superstructure paint, or just to the waterline?

[Martin Kedian]

All of the black is two pack epoxy paint the old bitumen was striped off completely as the two pack would react to it there were at least six layers

[MtB]

What a handsome boat.

 

A credit to you and to KEDIAN.

 

 

MtB

[Starcoaster]

Beautiful job.

[Mitchellmoxo]

What a handsome boat.

 

A credit to you and to KEDIAN.

 

 

MtB

 

thank u very much

[Guest]

Looks like a fine job to me.

[Sabcat]

Overplating, done right is no bodge

[jake_crew]

I do like the lines of a Harboro'boat esp the sharp end.

[Martin Kedian]

Always was a nice shaped bow plus a good length

[Nightwatch]

Looks to be a first class job in all respects.

 

Congrats to the owner and Mr Kedian.