C19 - Major Structural Issues - Advice sought

Power Boats only. Please include the boat type in your question.
TomTom
Active Poster
Active Poster
Posts: 461
Joined: Thu Nov 22, 2012 10:29 am
Location: East Africa

C19 - Major Structural Issues - Advice sought

Post by TomTom » Sat Nov 11, 2017 3:29 pm

So what was meant to be a simple transom extension has changed into a major rebuild at the very least.

Whilst I had the engine off to extend the transom, I decided to do a few modifications to my bilge. After grinding through some paint (so I could glue in a mounting block for a bilge pump), stinking smelly greasy grey water started seeping into the bilge from under where I had opened up the paint on the port side of the keel.

About 5 liters of the stuff came weeping into the bilge; on further inspection/digging and to my alarm I realized that I can slide a hacksaw blade all the way under the motor well bulkhead and the port stringers.

In the transom lockers, I had noticed a small crack where my chase tube comes out; water would sometimes get in here (I guess from where the hoses come into the transom well).

I decided I better open this up and check if there was any water in there; and whether this was the cause of my problem.

Well the PU foam was a little damp near where the chase tube came out - didn't think much of it till I dug all the foam out and there was a pool of water about 10 liters right at the bottom.

More frightening was that as I was pulling the PU foam out, it was pulling up the fiberglass laminations with it.

I decided to cut an inspection hole in front of the motor well bulk head on the port side; so one frame in front of the leaking transom well.

This is a total disaster... on cutting the pu foam out, you can litterly squish the fiberglass up and down.

I cut through this layer with a box cutter knife and to my horror, it appears that all the fiberglass has delaminated from the ply.

This is worse than just a gap under the stringers. This means that the entire inner layer of biaxial (which makes up the "monocoque structure" has delaminated.

The epoxy has turned to a sort of dark brown gooey, sticky grease; it was rock solid dry when I poured the foam 5 years ago; is this some strange chemical reaction?

Has anyone heard of this before.

Does this mean I am going to have to rip out all my stringers and frames?

How do I prevent this in future?



User avatar
jacquesmm
Site Admin
Site Admin
Posts: 27391
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: C19 - Major Structural Issues - Advice sought

Post by jacquesmm » Sat Nov 11, 2017 5:07 pm

Can you post pictures and tells which materials you used, in particular the type of plywood?
Where was the water accumulation? In some sealed compartment? On the sides of the motorwell? Foamed?
Epoxy does not melt even soaked in gas, I wonder what is happening.

I have never heard of anything like that.
What is the plywood condition?
Jacques Mertens - Designer
http://bateau.com

User avatar
jacquesmm
Site Admin
Site Admin
Posts: 27391
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: C19 - Major Structural Issues - Advice sought

Post by jacquesmm » Sat Nov 11, 2017 5:12 pm

I did a quick search and see some posts about the building of the boat. It would be sad if this was a material quality problem because you did a great job, beautiful boat.
Let's talk about the materials you used before jumping to conclusions, I see and read some things that worry me.
Jacques Mertens - Designer
http://bateau.com

Fuzz
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 6533
Joined: Tue Aug 02, 2011 4:23 am
Location: Kasilof, Alaska

Re: C19 - Major Structural Issues - Advice sought

Post by Fuzz » Sat Nov 11, 2017 11:29 pm

And would you post some pictures of all this also, please.
I hate to hear about anyone having this type of problems.

fallguy1000
Very Active Poster
Very Active Poster
Posts: 5452
Joined: Tue Jan 12, 2010 12:25 am

Re: C19 - Major Structural Issues - Advice sought

Post by fallguy1000 » Sun Nov 12, 2017 1:44 am

Ingress is a boat's enemy. Water found a hole.

Get it dried up and investigate. The worst wet area is the ingress source.

It is impossible to respond to you without sounding like a smartypants, but those rigging tubes are supposed to mount high up toward the top of the boat to avoid ingress if that is your source. A crack near a chase tube should never be near anyplace where it can allow 10 litres of water to enter the bilge. Forgive me if that is not the source and you find something else.

Best of luck.
My boat build is here -------->

viewtopic.php?f=12&t=62495

User avatar
BarraMan
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 1518
Joined: Tue Dec 11, 2012 3:44 pm
Location: Australia

Re: C19 - Major Structural Issues - Advice sought

Post by BarraMan » Sun Nov 12, 2017 2:34 am

For some reason I find myself quoting Cracker Larry yet again!

Remember, "Its only a thing"!

You built it - you can fix it!

TomTom
Active Poster
Active Poster
Posts: 461
Joined: Thu Nov 22, 2012 10:29 am
Location: East Africa

Re: C19 - Major Structural Issues - Advice sought

Post by TomTom » Sun Nov 12, 2017 8:04 am

Dear Jacques - I have posted a video on you tube as I couldn't figure out how to post videos here on the forum - the link is https://www.youtube.com/watch?v=cBtuOy95UPo and I will try and post the rest of it as soon as I can get fast enough internet. Cant get the other part to load at the moment - but if you poke around on "my channel" you will get enough of an idea.

To sum it up, on further investigation, I think that issue is far worse than I had initially thought.

I have opened up the sole towards the front of the boat and basically the delamination has pretty much spread everywhere. I am posting another video now which shows that the biaxial fabric is even lifting off the hull sides high up in the front locker of the boat.

I think that this is obviously some sort of failure/ strange chemical reaction on the part of the epoxy; and may or may not be something to do with the water in the hull - I am still in two minds over this.

You can see in the video that it is like the epoxy has broken down, it is sticky and gooey and I can smell amines; on places where it was on the ply wood, I can literally scrape it off with my fingernails. https://www.youtube.com/watch?v=OTkNGGBxM7M

I would never have carried on building had the epoxy not cured initially, so there must be something going on.

I know that the outside of the hull was sheathed using Ampreg 21 (www.gurit.com/sitecore/content/Old-Prod ... mpreg-21SP)

As I recall, I ran out of that and I believe that the inside was done with Atul Lapox B11 and K-41 hardener http://kianresin.com/userfiles/files/16-K%20-%2041.pdf

Which as I recall, this was very viscous and I may have mixed it and then placed the pot in a tub of hot water to lower its viscosity (which I believe is an approved technique) in order to get it to wet out the glass.

I live in a place where this is the only resin available, and I believe that I did run it by Jacques at the time.

Unfortunately, the whole inner biaxial fabric was laid in the same day, so what ever issues stem for the resin, they must be pretty universal to the whole sheathing.

Having said that, it surprises me, that there are places which are firm and strong (perhaps a better mixed batch from the same day, or the water never got to that part)...

All this is fairly mute at this stage, as I really can't see any other solution than to gut the whole inside of the hull, and hope that the outside, with the different resin is fine.

As far as the plywood goes, it still seems pretty solid, with no signs of rot.

I know that I have another post somewhere else about the plywood available here; that was not what the hull was made with; what I used was also stamped BS 1088, but was much heavier and redder in colour. And in that batch the 12mm sheets had 5 plies. In any case, I boil tested all the samples...
Including this latest lot - which has stood up to one hour of boiling, a night of freezing and an hour of boiling so far, so at least the glue is strong

All I can say is that this is all pretty devastating...

In answer to Fallguy1000 - the chase tubes were in a locker specifically so it couldn't come anywhere near any water - unfortunately - it is a boat, and water tends to get places. I would personally love to hear of a fail safe solution for passing PVC pipes which have some flex through epoxy resin, and being 100% sure that they wont develop a small crack between the epoxy and the PVC. I wrapped pipes with fiberglass tape in the past and then glued them in place, and found even this wasn't fool proof. I have not found PVC to bond well to epoxy; but then I clearly haven't had access to all the wonderful epoxies available in other parts of the world!

I was certainly under the impression though, that once cured and hard, epoxy was fairly inert; and that other qualities aside like viscosity, cure times etc, were more of a luxury to the builder than a necessity to the integrity of the boat.

As I said before, there is no way I would have continued building with semi-cured resin... and all my resin samples were tested before laminating to make sure that they cured.

I guess you live and you learn; and as the saying goes, "worse things can happen at sea".

Personally, I am strongly questioning the logic of adding PU foam and completely trying to seal the various lockers. I am talking from experience now as this will be the third build/ rebuild if you include my OD 18 where this system (or I) has/have failed to completely make them water tight. I am a reasonably meticulous person, so I can guarantee that it wasn't for lack of thought/ trying that water has gotten in there.

I think that next time each compartment between the frames will have a drain plug that allows any water that may have gotten in there to flow into the keel section. This still gives a boat like the C19 8 separate chambers.

I would of course appreciate all thoughts on the subject; mainly from the designer as how best to fix this?!!!

Eric1
Very Active Poster
Very Active Poster
Posts: 3045
Joined: Tue Aug 19, 2014 3:17 pm
Location: Spartanburg,S.C.

Re: C19 - Major Structural Issues - Advice sought

Post by Eric1 » Sun Nov 12, 2017 8:56 am

Absolutely hard to see. I'm sorry this happened to your boat. :( I wish you a smooth rebuild.

User avatar
jacquesmm
Site Admin
Site Admin
Posts: 27391
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: C19 - Major Structural Issues - Advice sought

Post by jacquesmm » Sun Nov 12, 2017 9:48 am

It looks like a plywood and resin issue.
This is what it would look like with polyester and regular (not marine) plywood.
Since it is all over the boat, we will not blame a tru-hull or hole.

I remember looking at the specs for your resin and it looked appropriate but what you got may not be to specs. I have never seen cured epoxy becoming gooey as you describe. Some epoxies are rubbery but once a resin cures hard, it stays that way and epoxy will not melt or dissolve.

Talk to your epoxy supplier, he should know if he had a bad batch but also, what type of plywood is this?
Jacques Mertens - Designer
http://bateau.com

TomTom
Active Poster
Active Poster
Posts: 461
Joined: Thu Nov 22, 2012 10:29 am
Location: East Africa

Re: C19 - Major Structural Issues - Advice sought

Post by TomTom » Sun Nov 12, 2017 10:22 am

This is a better overall impression of the issues https://www.youtube.com/watch?v=j4LTRu4 ... e=youtu.be

Unfortunately Africa is a continent not reknowned for taking tesponsibility for one's actions and that goes as far as hardware dealers and suppliers are concerned. The buck just gets passed down the line and I will never get to the bottom of what happened.

The dealer will say the supplier in India sent dodgy stuff, the guy in India will say that the transporter switched it, and the transporter who will say the guys at the ports did it etc!!

I have at least worked out how to import resin from South Africa in reasonable time; I believe the Ampreg 21 to be decent stuff?

I also don’t think the plywood is compromised. My OF 18 was built with WBP from the same supplier and it is still holding strong after 16 years despite having Water under the sole for at least 6 of those!

Let’s assume at least the plywood ok and the outer sheathing OK.

What’s the next step - gut the whole thing?

Post Reply

Who is online

Users browsing this forum: ray r and 4 guests