Cleaning rusty keel bolts on Hunter 380

[bigbrownpilot]

When we bought our Hunter 380 a little over a year ago, the survey recommended cleaning the rust off the keel bolts. As I've done some research on the bad things that can happen if you neglect the bolts (like your keel falling off), I've decided to tackle this project in the near future. Other than the fact that they sit at the low point of the bilge with about 1/2 inch of water around them, are there any recommendations out there? Was thinking I would use a siphon pump to get the remaining bilge water out, allow them to dry, spray with penetrant, then remove them one at a time, and use a wire brush to clean the stud, treat with a rust converter (zinc treatment, possible POR-15 Metal Ready), and re-install the nuts. Any suggestions are greatly appreciated!

 

[Don Lucas]

I use a wet/dry vac to get the last of the water out of the bilge.

But are you really sure you need to clean the bolts? The bolts on my 410 are 316SS, they don't rust. I think you may be wasting your time for nothing (post a picture).

 

[ALNims]

I use a wet/dry vac to get the last of the water out of the bilge.

But are you really sure you need to clean the bolts? The bolts on my 410 are 316SS, they don't rust. I think you may be wasting your time for nothing (post a picture).

I agree that you should approach this caution.

 

[ALNims]

I recommend that you contact Hunter first and see if they have a procedure including torque specs for the bolts before you attempt anything.

 

[fredanderson2000]

Hunter has a history of mounting the grounding bus plate to a keel bolt. This will eventually lead to electrolytic corrosion (the resistance of the connection will increase and cause arcing to the bolt). The end result is after about 15 years, the bolt will become useless. This can happen quicker depending on the amount of resistance and the current being drawn through the bolt. This occurred on a 33.5 I had. The repair was posted on the 33.5 boat modifications. I relocated the ground plate above the bilge floor out of the water after I fixed my broken bolt. Stainless corrosion will accelerate in the absence of air, but the oxidation on the bolts is actually a good thing. I agree with the other posts, and try to keep your bilge dry. The by-product is a better smelling cabin.

 

[Don Lucas]

Hunter has a history of mounting the grounding bus plate to a keel bolt. This will eventually lead to electrolytic corrosion (the resistance of the connection will increase and cause arcing to the bolt).

Interesting that this is the first time I've ever read this as some type of Hunter problem. I bet most boats are grounded to the keel.

 

[Steverhnm]

Keel Bolt Refreshening

I had a thread on this awhile back that had pictures of my rusted washers under my keelbolt nuts, I never did anything with the bolts but I still have plans to pull the nuts, replace the washers, clean it all up and seal under the washers with Butyl rubber, then put the bolts back on with Never Seize.

Problem is on my 1990 is they used carbon steel washers. I think they were just being cheap quite frankly. If there is any saltwater, they will corrode. When they corrode they expand. After expansion they will collapse., then you have loose nuts. But on a heavy keel you won't notice that until a crack develops and then you are too late for a simple fix.

I bought 316 SS washers from Fastenal ($6-8 each), they have a website, but I would suggest a local supplier if you have them, as they are slow.

I installed a shower sump (plastic box with small bilge pump) in the bilge (because El Max did - I copied his idea) to keep shower water out of the bilge. That was my major source of water. After I replaced my leaky raw water hoses and clamps I don't get any more seawater in the bilge anymore either.

The next challenge is getting a socket wrench that will fit over the long bolt heads. I found a farm implement place for the 1-1/2 socket, but I had to make the one for the 1-7/8" socket. I basically got a an deep impact socket, cut it in half with the chop saw, and had someone weld on a piece of 4 inch long pipe, now I have a socket with enough depth for the big bolt.

For the lightning protection wires I drilled and tapped a 5/16 bolt onto the top of the large bolt. Now my lighting protection wires are out of any nasty water and I am guaranteed a solid connection to the keel and no corrosion on the connection. The old way with the rusted metal plate laying in the water was a poor design idea.

Next time I go down there (to the boat in Mexico) I will attempt to "freshen the bolts". It will require some PB Blaster, a breaker bar, and probably a cheater bar, as just the breaker bar was not enough.

Just sharing my thoughts on Keel Bolts.
Previous Post:
http://forums.hunter.sailboatowners.com/showthread.php?p=1054654&highlight=keel bolt

 

[Scott B]

Hunter has a history of mounting the grounding bus plate to a keel bolt. This will eventually lead to electrolytic corrosion (the resistance of the connection will increase and cause arcing to the bolt). The end result is after about 15 years, the bolt will become useless. This can happen quicker depending on the amount of resistance and the current being drawn through the bolt. This occurred on a 33.5 I had. The repair was posted on the 33.5 boat modifications. I relocated the ground plate above the bilge floor out of the water after I fixed my broken bolt. Stainless corrosion will accelerate in the absence of air, but the oxidation on the bolts is actually a good thing. I agree with the other posts, and try to keep your bilge dry. The by-product is a better smelling cabin.

What is flowing through he connection? They are grounded for lightning protection only.