Broken thru hull

[Yooper]

I was removing my air conditioner pump and barely bumped my live well thru hull. To my surprise the thing snapped right at the hull below the shutoff. Lucky I had a set of tapered hardwood plugs and was able to stop the water coming in. ( If you don’t have a set, you might want to pick one up)
I’m wondering if this is common on Grady White and should I be replacing all the thru hulls below the waterline? It’s a 2007 28ft Sailfish that I’ve owned about 2 months.

 

[DennisG01]

Wasn't it bronze? That would be uncommon to snap one of those off - it may have sustained previous damage and just showed up. Likely from being stepped on.

But, this has always been my contention with mounting shutoffs directly to a thru-hull. There really should be a triangular-base flanged ball valve used. It's a MUCH stronger solution. Other manufacturers use them - I'm not sure why Grady resists.

 

[Halfhitch]

Wasn't it bronze? That would be uncommon to snap one of those off - it may have sustained previous damage and just showed up. Likely from being stepped on.

But, this has always been my contention with mounting shutoffs directly to a thru-hull. There really should be a triangular-base flanged ball valve used. It's a MUCH stronger solution. Other manufacturers use them - I'm not sure why Grady resists.

I agree with Dennis. It's hard to understand why Grady would not install a real tri-flange seacock as standard instead of the cheesy inline valve screwed onto a threaded thru-hull. The wall thickness of the thru-hull tube is very thin at the bottom of the threads and it is subjected to the torque of the opening closing forces of the valve. Not good, and a real hazard if it fails far offshore and you aren't prepared like the OP was with the proper tapered wooden plugs. Good on him!

 

[Fishtales]

First, everyone needs a set of plugs and a couple tubs of Stay Afloat on their boats. If you don't have them onboard, you really need to get. I'd be surprised if they were bronze, but anything is possible. Another reason not to put excessive pressure on your ball valves if they are not working properly and test/address if required before splashing.

 

[Yooper]

I like the thoughts on the heavier triangle based thru hulls and will pursue that avenue.
After a little investigation we found that I possibly had some serious stray current corrosion in the past couple months. After pulling the boat today I found the 2 month old sacrificial anodes had really deteriorated and there was a white powdery substance all over the part of the engine brackets below the surface. None of the boats next to me in my marina have had any issues to date. I did just return from 6 days in the Bahamas where I stayed at a marina with some questionable electrical. I have no idea if it’s my boat or it was the boats or shore power in the Bahamas.
We were a little surprised that Grady didn’t have any sort of grounding/bonding system. Is this something that’s needed?
Any suggestions would be appreciated.

Thanks
The Yooper

 

[DennisG01]

Bronze?

But... you're making an assumption that it was Grady that installed it. Maybe it was a previous owner's install. Either way, yes, any underwater hardware should be tied together through a common bonding system.

Are you sure you have the right compostion of anodes on there? If the anodes wore away that fast, it's possible that they are Mg.

 

[Yooper]

Just got pictures of my outboard brackets. This happened in a 3 week period including a Week in Old Bahama Bay , West End Bahamas. I used shore power for 6 days. This is why I figured electrolysis played a part in the thru hull failure. I’m replacing all the thru hulls and bonding them. Also checking my complete electrical system for problems.

 

[Fishtales]

Wow. Have not seen that before.... Keep us informed of your findings.

 

[Yooper]

That’s the general response I’ve been getting.

Stay tuned

 

[Legend]

Can't believe that all of that occurred in a 3 week period Is there permanent damage to al those components pictured?

 

[Yooper]

Trying to establish that. They appear ok, but need to put some stress on the bolts and thru hulls.

 

[DennisG01]

From what I'm seeing in the pictures, and maybe I'm missing something, that simply looks like some type of growth. I don't see any corrosion. The growth could happen because the metal hasn't been anti-fouled.

 

[Yooper]

I hope that’s the case but the new zincs installed a couple months ago are about gone.

 

[DennisG01]

I hope that’s the case but the new zincs installed a couple months ago are about gone.

See my comment above about that.

Which anodes are you referencing? The main anode looks barely touched (bonded properly?).

I do see what looks like a bunch or barnacles starting to grow - but that's a different situation than corrosion.

 

[Yooper]

Those are the ones. The mechanics told me that they were bad. Not sure about the about the bonding. I’m going to the boat tomorrow and clean things up and get a better look. This is all new to me so I really appreciate your input.

 

[DennisG01]

Those are the ones.

Huh? Which ones? You can't say "those"... I'm not next to you to see what you're pointing at!

 

[seasick]

I can't tell how bad the bar anode is from the picture. The growth is some species of barnacle and it looks to me that they seem to like whatever the bottom of the motor bracket and tilt pump were painted with. First thing to do is clean up the slime and growth to see if it is superficial or actual corrosion taking place. You made need something strong to get the barnacles off completely. Although muriatic acid works well, it is a dangerous chemical and needs special care. You can start with over the counter options from a marine supply store and may not need to go to the strong acid.
Once cleaned up, you need to prep the metal:apply aluminum compatible primer and antifouling paint to the parts that sit in the water ( not the anodes of course) Also make sure that the surfaces that the anodes rest on are paint free, just bare metal.You have to maintain a good electrical connection between the motor and the anodes.

Wear the appropriate protective items when cleaning and keep your bare skin away from the barnacles and ooze. I have seen some really wicked infections from barnacle cuts.

 

[Yooper]

Thanks to all. I’ll post pictures after cleaning. I’m starting to think the broken thru hull is a separate issue.

Stay tuned

 

[Yooper]

Sorry to DennisGO1.
I’ll try to clarify. I meant all the ones I sent photos of. I have twin 250 Yamahas and the pictures were of each engine and the looked the same.

 

[DennisG01]

Sorry to DennisGO1.
I’ll try to clarify. I meant all the ones I sent photos of. I have twin 250 Yamahas and the pictures were of each engine and the looked the same.

The only anodes, I believe, for your engine are the main anode (in 3rd pic), along with the one under the anti-cavitation plate. There are no other anodes on the lower engine. You may have up on the engine block, not sure on that - check online parts diagrams.