Severe aluminum shaft log corrosion/deterioration

"Wow! Amazing those props even turned with that kind of damage! Glad you got everything resolved thought. Were there bronze set screws in the cutlass bearings by any chance? Any clue what caused your corrosion?

I'm having an epoxy barrier coat put down under the stuffing boxes and in the shaft pump well to address some of the pitting that is occurring. Did you run into any similar issues with your Broward?"

To edit my post, we cut 6 INCHES not feet off the forward end. there was quite a bit of plate corrosion in the "well" below the shafts. This area had resin of some sort poured into it to try and get water to flow forward to the engine room through conduit that the water cooling hoses ran thru. That made no sense, the hull was lower than the conduit, so they poured goop in there to raise the "floor". Needless to say, lots of corrosion from salt water getting under the "resin" and an incredible stink that the owners had complained about for years!

We replaced the old Aluminum stuffing boxes with lasdrops, put a shortened cutlass bearing in that end of the log and used Belzona to seal up and protect the plating. We also replaced the remaining Cutlass bearings and of course reshot (laser) and chalkfasted the whole thing. It took a lot of time to get the alingment right as it was off by huge amounts. Ended up having to move the Engines a bit, replace rusted through motor mounts and custom build a new tranny mount bracket after one was found to be Broken!

Years of Neglected are the answer to how this happened. My friend took over the boat a few months ago and started digging. The owners had the boat built in 1988! had to replace some hull plating in the ER due to metal and dirt in the bilge, hiding under "drip pans"! All in all we tore a Ton of stuff apart and it is a better boat for it.

Now most importantly, everything that everyone has posted about the welds is correct, those are horrible. The logs do not look like they were cleaned at all. Do it over!!!!!!

Thats just plain BS, you spool out new clean aluminum wire and it's covered by a argon gas shield. Where would the soot come from???? MIG or TIG with argon gas will leave the plate as shiny as it was before welding................In your case the surface wasn't prepared and cleaned correctly, thats where the soot came from.

It should look like the pics Bill106 posted.

Walt

Hi,

I agree with the previous comments about the appearance of the welds.

The area should be ground as it appears to have been and the wire brushed with a SS wire brush, sometimes some solvents or something left from the initial treatment seem to cause weld problems.

If your "independent" expert says they look good, I would call into question his abilities.

For definitive proof of the welds integrity have them x rayed before you get the tanks pressure tested.

Basically the ones outside look like cold overlay, poor penetration and dirty surfaces to me.

Hi,

I have sent Photo 1 from Post 17 to a couple of guys I know who between them have more welding experience than most will accrue in a lifetime.

One is an ABS Senior Surveyor, the other a welding superintendent in a major shipyard.

I will post back with the opinions

Just read today's posts ... geez, that really is an ugly bunch of welds! It looks like something I might have done while trying out a new spool gun.

That soot is from using 5xxx series wire and dragging the torch rather than pushing it. Some of that soot will be included in the weld itself and lead to porosity. A little bit of soot is all but unavoidable because it is from the magnesium in the metal. If you use a wire brush on a die grinder it will actually combust and make a neat looking expanding ring of orange that looks like a grass fire as seen from the air.

I guess if you slobber enough metal on something you might get structural support but usually a weld is about as good as it looks and those look like crap, not matter what the locals say about it.

The weld photographs depict weld regions which appear sound, and regions which appear quite poor. For any given weld joint the entire weld, both internal and external to the hull must be sound. I believe these welds are going to be problematic within a period of time which will be quite short of their intended service life. Either deal with them now, or someone will be dealing with them in the not too distant future.

Scallywag,
I'm no welder but there is NO penetration in the tube in the last pictures you posted.
Peter

That was definitely MIG and inside the shop with no wind to blow the gas away from the weld. Some were inverted and just about any orientation but I couldn't tell a difference. I am by no means an expert in welding but those guys we hired are the absolute best I've ever had the pleasure of working with. There is a huge difference in tower stick welding (TIG) and plate welding and I've got a renowned tower builder across the street but when these guys were at work they came over and stood slack jawed at the artistry being created. One of the guys had over 25 years of aluminum hull building experience but his apprentice was nearly as good after only tweo years.

The second set of pics you posted up looks much better to my untrained eye
and mainly because the start/stops looked properly done. One thing those OA/SWS guys taught us was the proper way to do that was to grind back into the end of the weld before restarting.

Be leery of soliciting advice from general purpose welders. I've discovered there is a specialty within a specialty when it comes to proper metal hull building techniques.

Try the professionals at Miller, they might not agree with the ones you have spoken to. Or, if you like, go take a look at an aluminum boat built by Derecktor or any another builder with a reputation for quality aluminum boat building.

AL MIG welds from Miller:

I am not a professional welder but i enjoy metal fabrication on the side and the welds done on this repair are not adequate at all.

First of all a repair like this should be TIG welded by a professional. Due to the fact that this hull have been sitting in salt water for this long, there is a lot of oxidation and contamination in the base metal. Welding alum. is very techincal and should only be done by a professional. There is also no cleaning action around the foot of the welds. weld is also too cold. You should also check what filler metal the welder used. 5356 (or 5xxx series) is marine grade alum.

Lack of "stack of dimes" DOES NOT mean it is a bad weld. the stack of dimes comes when you add filler metal to the weld puddle. If the welder feeds filler metal at a faster pace or lays wire then the ripples come much closer together and you can lose that affect without sacrificing the joint.

I wouldn't trust those welds one bit.

On a side note cleaning the alum with Stainless Steel brush is common practice. (That brush should not be used on any other metal though)

I've seen better welds but I'm not a weld expert, however we have had recent experience on bearings installed in Al ships, there had been problems with previous shaft bearings where corrosion was seen between the bearing and the bearing carrier/tube/strut. This caused some bore closure and tight running which gave shaft and bearing wear. These were composites that were freeze fit so no metal to metal issues just pockets of salt water. These were changed for clearance fit fully composite phenolic bearings these from Australia were also resistant to marine growth, so far (three years) so good, very low wear rates and no shaft damage or corossion. So epoxy bedding to manufacturers clearances seems to work well.