Replacing single rusty keelboat

[dirigible]

Hi, all.
I'm the new owner of a 1991 Oceanis 370. One of the keelboats--an easily accessible one, with the lightning ground cable attached--is very rusty, while the others are all clean. I would like to replace it. Just wondering what would have caused this, and if this is an easy-ish DIY job?

 

[kappykaplan]

Just wondering what would have caused this,

My first guess is bi-metallic corrosion. Welcome to the forum!

 

[Ralph Johnstone]

Firstly, welcome to the site.

Just wondering what would have caused this,

With the corrosion that heavy and that uniform, my first guess would be that someone accidentally slipped in a plain carbon steel keel bolt during the initial boat construction. HOWEVER, having said that, the chance of also having the small reinforcing plate as accidental carbon steel as well really seems low on the probability scale. Got to wonder if somehow the lightning ground is involved when other bolts are in good health.

First thing to do, before you can even discuss this problem is to check it out with a magnet.

and if this is an easy-ish DIY job?

A bit of a bugger unless you're prepared to drop the keel.

I would suggest checking to see if there's water coming in from under the washer or just on top of the bolt from other sources within the boat. If nothing from underneath, you may want to consider installing a barrier to ensure the bolt stays dry. Permanently

No insult intended here but from your question, this problem is well above your pay grade. You likely excel in other areas however. You may want to bring in a pro (no dock rats here) for their opinion. Several questions to be looked into here i.e. does the loss of one bolt only compromise the keel along with several others questions.

 

[dirigible]

Firstly, welcome to the site.



With the corrosion that heavy and that uniform, my first guess would be that someone accidentally slipped in a plain carbon steel keel bolt during the initial boat construction. HOWEVER, having said that, the chance of also having the small reinforcing plate as accidental carbon steel as well really seems low on the probability scale. Got to wonder if somehow the lightning ground is involved when other bolts are in good health.

First thing to do, before you can even discuss this problem is to check it out with a magnet.

A bit of a bugger unless you're prepared to drop the keel.

I would suggest checking to see if there's water coming in from under the washer or just on top of the bolt from other sources within the boat. If nothing from underneath, you may want to consider installing a barrier to ensure the bolt stays dry. Permanently

No insult intended here but from your question, this problem is well above your pay grade. You likely excel in other areas however. You may want to bring in a pro (no dock rats here) for their opinion. Several questions to be looked into here i.e. does the loss of one bolt only compromise the keel along with several others questions.

No insult taken. That's why asked the question. I'm reasonably handy, but want to approach any keel repairs with caution. I had a survey done at time of purchase, and the surveyor's opinion was that this is not a significant immediate concern, but something I probably want to address in the near future. We just hauled out for winter storage, so now seems like a good time.

 

[Ralph Johnstone]

First thing to do, before you can even discuss this problem is to check it out with a magnet.

Let us know.

 

[dirigible]

Let us know.

The boat's a 4-hour drive away. I'll let you know next week.

 

[Ralph Johnstone]

OUCH ! Didn't realize it was that far away. I don't think too much will happen in the next week or so, soooooooooo no rush.

On second glance at your picture AND after the first of several coffees to get my head in gear, it looks like the SS post, nut, and washer for the lightning ground cable are happy enough and showing no corrosion, so that would seem to up the probability of the keel bolt being plain carbon steel. Your magnetic test will remove any guess work.

 

[dirigible]

No worries. I'm heading there this coming weekend to winterize it. Will check.
How will the bolt material change how I proceed? I assume in either case I will have to replace it.

 

[jssailem]

Hi @dirigible interesting choice of avatar.
Welcome to the SBO forums.

I have been looking at your image. I have several observations.

1. The hoses and valves appear to be normal, but the metal handles on both have considerable rust. Do the valves operate smoothly? Are the rusted portions of the valve compromised?
2. The area identified in the red circle, I believe, is the keel bolt, though, through the rust color, it is difficult to discern. Is it a coincidence that the rusted valve handle is directly above the area of rust? What caused the scratch in the gelcoat? Was something removed? Repaired? Is there a rusted metal plate being used to secure the keel bolt?
3. The clean stainless steel bolt looks out of place. It appears too small to be a keel bolt for a 370 (37ft boat). Stainless would be a poor choice for a through bolt to transmit electricity to an anode or a lightning plate. Where does the wire go? To what other parts of the boat is the wire connected?

I know the challenge of being 4 hours from your boat. If, like me, the sailing options are more grand where the boat is moored, then the distance is less significant.

Fair winds.

 

[Ralph Johnstone]

How will the bolt material change how I proceed?

We have to know what we're dealing with before we make any wild guesses about how to approach the problem. The more information we can collect in the beginning, the better our guess as to what needs to be done in a financially acceptable manner.

in addition to what I've already mentioned, you'll also need to check the torque on the nuts of the other SS keel bolts. No rush on those numbers yet. Don't bother with trying to check the rusted nut and bolt as it's not going to move.

 

[Davidasailor26]

We have to know what we're dealing with before we make any wild guesses about how to approach the problem. The more information we can collect in the beginning, the better our guess as to what needs to be done in a financially acceptable manner.

in addition to what I've already mentioned, you'll also need to check the torque on the nuts of the other SS keel bolts. No rush on those numbers yet. Don't bother with trying to check the rusted nut and bolt as it's not going to move.

Some notes I’ve seen on Beneteau keels say they use galvanized bolts on all iron keels, and stainless nuts onto threaded rods for lead keels. I presume the 370 has an iron keel, so all of the bolts are likely magnetic steel. Maybe something went wrong with the galvanizing on that bolt, maybe a previous owner replaced it with a more mild steel bolt, or maybe the seacocks leaked at some point and exposed that one to extra salt.

 

[Indysailor]

Does this prior thread discussing a somewhat similar situation and a Beneteau help?

keel bolts ? - buying boat

Hi, I am delighted to join the forum. Probably I will become new owner. I am looking to buy an Oceanis 400 in Italy. I found boat. I checked most of the boat and I found partly rusty keel bolts. The first one is rusty. The boat is year 93. Do you see this as a bigger problem? Is this normal for...

forums.sailboatowners.com

 

[Ralph Johnstone]

Good memory @Indysailor , and bad memory on my part as I put in a few thoughts to that post back in '21.

 

[Ralph Johnstone]

@dirigible , a few more thoughts for your consideration trying to keep in mind that you're a four hour drive away from your boat :

1. Magnetically test all the bolts and record.
2. Grab lots of close up photos of all bolts or nuts or studs or whatever it is that holds your keel on to the boat. We want to see if they're nuts or bolts that are exposed.
3. Closely examine how your boat is supported now that it is on the hard. 99% (or thereabouts) of the total weight of the boat MUST be sitting on the keel and the stands are only there to balance the boat. We recently had a picture in here where a boat was sitting with the entire weight of the boat supported by the stands. Nothing on the keel. @Indysailor , try your memory on that one about 2-3 years ago. I should have saved the pic but it's buried under several thousand posts by now.
4. Take a set of socket wrenches (in the neighbourhood of 1"), extension rods, and a breaker bar to test ONE ONLY of the fastening devices.
5. Test ONE ONLY of the fastening devices to see if it will back off. Do not test any of the others until you know what the desired torque is.

With all of the info @Davidasailor26 and @Indysailor have provided, who knows, this may be your lucky day and the entire job will cost no more than pocket change. Seeing as I have proven beyond a doubt that I know nothing about Bene keels, this would be a good time to start researching the literature here in the SBO archives for an owner's manual for a '91 Oceanis 370. What we're looking for is the required torque on the whatever it is that's holding the keel to the boat.