# Fixing Keel Rust is a real GRIND!!! (PIC HEAVY)



## Bene505 (Jul 31, 2008)

As promised on another thread somewhere, here are some pictures of my keel grinding on our Beneteau 50.

Warning this is very picture heavy. Don't use the "Quote" button, use "Post Quick Reply".

Here is a long sequence of pictures. I'll let them do most of the talking. Note that there was a lot of grinding -- from start to finish that day, about 2 hours worth, with a 4.5 inch Makita grinder. (Hint - use older/worn grinding wheels that have a smaller diameter for grinding out hard to reach areas.) I begin the pictures after I've removed the paint and previous barrier coat, and after a night with exposed metal. (After several hours of grinding the day before, I had to leave quickly to get 2 stitches in my knuckle.)

Throughout the day, I used a wire brush on a reversible drill to clear everything away and show me where there was still rust spots. Then I went after the rust with the grinder. I repeated that many times. In one place the night before, I found a "fault" which was 1/8 or 1/4 inch below the surface. I felt I needed to grind to smooth. The fault would certainly make a path for future rust to follow.

Somehow, I felt like a dentist. Now there's a scary thought.

Since these pictures, (this past Sunday) I did a full day of grinding under the keel, aft of the wooden block. That's with about 6 inches of clearance. I was tucked right up with my (very protected) face next to the keel, so I could see what I was doing. Driving home that night I counted my blessings that I didn't get seriously hurt. I only got a nick through my new leather gloves, and something under both contact lenses. THAT GRINDER TRULY SCARES THE CRAP OUT OF ME. I'm really not looking forward to about 5 more days of grinding, most of them under the keel. That's what I think I have left.

By the way, there are 2 rusty spots where the keel meets the hull (fore and aft). I have no idea how to do those.

Anyway, enjoy the pictures. Any feedback welcome.


















































































































































































































































































































































































This is very picture heavy. Don't use the "Quote" button, use "Post Quick Reply".


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## brak (Jan 5, 2007)

never mind, sorry - I re-read your post. Benny - so the keel is bolted on


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## smackdaddy (Aug 13, 2008)

Great work Bene. I can see that whack on your finger too. What's the white stuff?


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## doubleeboy (Jul 21, 2008)

Sure would be nice if manufacturers would give up on iron keels. What a pain. I have one on my Dehler 39 which has rust spots. Boat is on the hard right now, boat yard said they could fix spots but no guarantee that they or their cousins would not appear next year, proper prep and barrier coat would help but no guarantee.

So I chickened out for this year, scrape, sand a bit, paint and go sailing. Next year I will likely be the one cursing, grinding iron for days. 

Marvelous pictures, you are an inspiration. Hope your body survives the ordeal.

michael


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## Bene505 (Jul 31, 2008)

Not 100% sure that I'm doing it right. It feels like I'm grinding way to much. (I have taken off more keel than rust has done.)

SERIOUSLY... AM I GRINDING TOO MUCH???

.

As for underneath, it's really hard to get at all of it. A small (250 watt) worklight works, because it fits right underneath (not the 500 watt in these pictures). Light is everything here. I may also invest in a mirror. I do use my digital camera underneath, in movie mode. I slowly move the camera while calling out the position of the camera (how many inches from the wood block). The I sit and look at it to see where the rust spots still are.

Underneath gets harder because the keel widens as you go aft. For instance, 2 feet wide, with 6 inches of clearance to work with. You have to really get under there to get the rust out. After 6 hours of that, holding that tiger of a grinder, my arms get really tired. I'm planning on doing it in shorter sessions. The grinder requires continuous attention and finger strength. It's not something you want to do when tired.


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## Bene505 (Jul 31, 2008)

smackdaddy said:


> Great work Bene. I can see that whack on your finger too. What's the white stuff?


Thanks smack.

Zinc Oxide, I had a big tube of it left over from my lifeguarding days. (grin)

It's Interlux 2000e in white.


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## PalmettoSailor (Mar 7, 2006)

Yep, the fear of this project was the major factor that tipped the scales from Bene to Catalina for me. Given the vintage boats in my price range, I knew I'd be facing this sooner rather than later, so Catalina's got the nod. The two brands share a lot of basic construction methods in common and there are several features Benes offer that I really like, but this is one onerous task I know I won't have to deal with.


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## smackdaddy (Aug 13, 2008)

I'd do this kind of thing too, you know - but I'd screw up my manicure.


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## Gramp34 (Oct 5, 2006)

Boy, what an ugly, nasty task.

The first thing I'd do is check if the marina would hang the boat in the travelift straps somewhere in the yard and let a sandblast contractor come in and blast the bottom of the keel clean. (You're going to have to pay for the travelift to move your blocking, anyway.)

(Edit: The second thing I'd do is check for a yard that would allow sandblasting the keel if my current yard said no.)

Failing that, I'd rent or buy a 7" grinder, then have the boat hung overnight in the travelift straps with the keel bottom about waist high. Then sit in a lawn chair in such a way that my elbow would be on the armrest while supporting the grinder. This would be awkward, but it would keep you from having to support most of that tool weight while working.

Keep the wheel guard between you and the wheel.

From the amount of material you're removing, it looks like the iron is pretty porous (cheap casting) and punky from rust. If you can seal up the bad stuff and keep water out it should be OK if left on. The question is how well you can seal it up, especially on the bottom where it's going to be abraded when grounding.

One idea would be to leave the deep pits, then when you do the repair, add some layers of fiberglass, or even kevlar, cloth to the epoxy to protect against abrasion better.

If that eventually fails, you'll need to go back in and grind everything out, but if it holds OK, you'll save a lot of awkward grinding now.

Good luck,

Tim


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## KeelHaulin (Mar 7, 2006)

I think you are taking too much metal off. Just have it sandblasted, grind out any pits and then fair it with an epoxy filler (putty made with chopped glass and silica). Don't follow the cracks with the grinder; it won't make much difference in the strength or life of the keel if the rust is in there (it's like surface cracks in a sidewalk).

It's possible that if you use a zinc fish attached to a keel bolt when moored it will help minimize the corrosion of the keel if it has been exposed by flaking paint or scraped on the bottom. That's if your keel is not bonded to a zinc on the hull already.


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## scottyt (Jul 19, 2008)

personally i would use lots of phosphoric acid to eat the rust off. it also gives the iron a iron phosphate coating with helps protect from rust, and holds paint very well. i know acid works well on things not in the water, i dont know how it would work for an iron keel thou. why is there no zinc on your keel?


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## Bene505 (Jul 31, 2008)

I get the feeling that I'm doing it the hard way, trying to save a few bucks and not hire a sling, the marina, a sandblaster....

The advice is much appreciated!!


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## timebandit (Sep 18, 2002)

Rust converter from an automotive paint supply store.
Wire brush all the paint and loose rust and just paint it on.

I think it is phosphoric acid.

Cost less than $20 a quart.

follow the direction on the bottle.


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## mitiempo (Sep 19, 2008)

Maybe I'm wrong, but wouldn't a zinc stop least noble metal from dissolving while not doing much to stop rust which is a result of water and oxygen being present?
Brian


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## tager (Nov 21, 2008)

When iron converts to rust it gives up electrons LEO. This means that if you have some really generous metal, say zinc, it should theoretically keep the iron in good shape by donating lots of electrons GER! 

LEO GER!


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## Bene505 (Jul 31, 2008)

*Could it be this simple???*



timebandit said:


> Rust converter from an automotive paint supply store.
> Wire brush all the paint and loose rust and just paint it on.
> 
> I think it is phosphoric acid.
> ...


Could it be this simple???

.


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## bubb2 (Nov 9, 2002)

Bene505 said:


> Could it be this simple???
> 
> .


No, phosphoric acid is a organic compound meaning it is water soluble. It is simply liquid Naval Jelly. It turns rust to iron phosphate. Bottom paint is not water proof. Barrier coat is. But to get barrier coat to stick the best you need to apply to shinny metal.

If you would just paint over phosphoric acid, the problem is once you splash the boat and it gets wet you lose the protection.


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## Bene505 (Jul 31, 2008)

Thanks Bubb2. That helps a good deal.

Not sure I mentioned it above, but I'm planning to do this in small patches. It will mean more trips to the boat, but don't we all need that anyway?


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## timebandit (Sep 18, 2002)

I just meant that it was easier to deal with the rust.

You still have all the steps to protect the metal that you normally would do.



bubb2 said:


> No, phosphoric acid is a organic compound meaning it is water soluble. It is simply liquid Naval Jelly. It turns rust to iron phosphate. Bottom paint is not water proof. Barrier coat is. But to get barrier coat to stick the best you need to apply to shinny metal.
> 
> If you would just paint over phosphoric acid, the problem is once you splash the boat and it gets wet you lose the protection.


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## Bene505 (Jul 31, 2008)

So I can use the phosphoric as a "wash" to get all the rust out, and then apply barrier coat etc.?

Quesiton -- does the water in the "wash" casue rust (or flash rust onthe surface), or will it be good to go once the liquid dries.

...seriously considering this approach!


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## fullkeel7 (Apr 16, 2008)

Bene505, Do you think the crevices in the iron are due to casting the iron or due to water intrusion of the bottom paint? I'm looking at a boat with an iron keel. How's your keel to hull stub mating seam look and do you have any keel bolt issues? Thanks, and good luck with it. Bob


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## bubb2 (Nov 9, 2002)

Please, reread my post #17. If you can get it down "shinny metal" with chemicals with out leaving a residue, go for it. The tried and true way is to grind and I know it is a pain in the arse. I have done it. Quick and easy is not the best way most times. But if you do it right you will not have to touch for 10 years, less new bottom paint.


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## Bene505 (Jul 31, 2008)

Thanks bubb. I may go with an acid and then flash-grind the surface to get clear metal for the barrier coat. The acid can't hurt since it will only really be attacking the rust, and in places I can't reach.

But then will a vein of disolved rust result in an air bubble under the eventual barrier coat? That would be just begging for water intrusion -- especially under 6 feet of water pressure, right?


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## bubb2 (Nov 9, 2002)

remember us talking about the wire brush! There was a reason.


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## BOLTER33 (Apr 9, 2008)

How long did you know about the rust? I Have a 2005Beneteau 42 cc hauled and painted last year with no problems, now my diver says I have rust on keel. I think I want to wait another year to fix it, because the rest of the bottom paint is in fine shape. Do you think its a bad idea to wait?


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## cruisingdream (Feb 7, 2007)

If your boat is grounded thru the keel, as many with iron keels are, dont put a barrier between the bottom of the keel & the water (dont paint leave a bare spot on the bottom out of sight)


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## cruisingdream (Feb 7, 2007)

If your boat is grounded thru the keel, as many with iron keels are, dont put a barrier between the bottom of the keel & the water (dont paint leave a bare spot on the bottom out of sight)


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## KeelHaulin (Mar 7, 2006)

I don't see the reason why you would want to grind away your keel as opposed to rust doing the same thing over a much longer time. You should remove the rust, but don't grind huge amounts good metal off (chasing veins of rust) to expose more good metal that will at some point also rust away.


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## Bene505 (Jul 31, 2008)

bubb2 said:


> remember us talking about the wire brush! There was a reason.


Yes, a full wire brushing comes right before I put the barrier coat on.


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## Bene505 (Jul 31, 2008)

BOLTER33 said:


> How long did you know about the rust? I Have a 2005Beneteau 42 cc hauled and painted last year with no problems, now my diver says I have rust on keel. I think I want to wait another year to fix it, because the rest of the bottom paint is in fine shape. Do you think its a bad idea to wait?


We bought the boat in July. I don't remember how much rust was there. I'll have to check the survey to see if it was mentioned.


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## Bene505 (Jul 31, 2008)

cruisingdream said:


> If your boat is grounded thru the keel, as many with iron keels are, dont put a barrier between the bottom of the keel & the water (dont paint leave a bare spot on the bottom out of sight)


I'd rather leave a bare spot where I can see it. Maybe a few inches up the side, where the bulb is reall thick.

Is this for lightening protection? Can you say more about this? I'm not sure the rust that would be there within a day would be conductive, so I'm not sure this would help.

Regards


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## JimsCAL (May 23, 2007)

In the 20 years I have owned my Cal 9.2 with an iron keel, I have stripped, sanded, and painted the keel with Interprotect 2000 three times. Not a terrible job. This approach seems to last about 5-6 years before the rust spots become an issue again. No way I would grind the keel as much as you are Bene505. What yard in Glen Cove are you in? I'm in Glen Cove Marina. Stop by if you like to see my 27 year old iron keel.


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## sailingdog (Mar 19, 2006)

*Don't leave any of the metal bare. *_If you think that lightning will notice or care that there is a .1" layer of epoxy, barrier coating and paint in its way, you're delusional... __If your boat gets hit by lightning‚ it will make its own path from the keel to the water... _


Bene505 said:


> I'd rather leave a bare spot where I can see it. Maybe a few inches up the side, where the bulb is reall thick.
> 
> Is this for lightening protection? Can you say more about this? I'm not sure the rust that would be there within a day would be conductive, so I'm not sure this would help.
> 
> Regards


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## bubb2 (Nov 9, 2002)

Bene505 said:


> Yes, a full wire brushing comes right before I put the barrier coat on.


to get all the little debre out of very little crevice before you paint! the paint / barrier coat sticks better!


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## timebandit (Sep 18, 2002)

Bene505

You might wanna read this--http://www.alan.net/prgshoptips/rustconv.html

As to the method you are using now have you considered how much filler you will need to fair the keel once you are done??

Try using a drill with a sanding disc with a flexable rubber backer and paper that looks like gravel for the first cut and dont go to smoth so the primer and filler will have something to hold on to.


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## Bene505 (Jul 31, 2008)

Update -- better way much simpler and no grinding!

I know it's been a long time since starting this thread. There's a much better way.

First -- The Interlux Etch Primer (2 part, yellow) is useless. I've switched to Corroseal (1 part) and it's amazing. 
Second -- No more grinding! I've switch to wire brush only, with the use of naval jelly to get/convert any remaining rust.

The whole job takes 1/20th the time, no grinder (this is not scary) and best of all, it works!

Here's the full procedure for iron keels:

1) Choose a dry day. Have some old towels ready. Have a hose ready. (Don't fear the rinse cycle.) Use nitrile gloves.
2) Wire brush any rust spots using a heavy-duty wire brush. Harbor Fright has them. Feel free to ""follow" rust that you find under your existing barrier coat. But note that it's easier to work in zones, especially as you get used to the procedure. Wire brush until nearly all rust is gone.
3) Apply naval jelly (phosphoric acid) to bare metal. Wait a few minutes for it to work. Apply more if needed, again and again. Just glop it on, you don't have to be neat.
4) Over on the side somewhere, pour Corroseal into a container so it's ready to apply with a paint brush. Corroseal is available from Home Depot in gallon size. But it goes on thin. After years, I've used about a pint and shared another pint with others.
5) Rinse-off all the naval jelly with a hose, use your hand to help where it sticks a bit to the metal. Hose can be on a low-flow setting.
6) Quickly dry the keel with towels. Spend about 10 minutes getting it dry.
7) Once dry, immediately paint the exposed iron with Corroseal. Two coats works.
8) Relax. There's no more rushing, the iron is now protected. Go on vacation. Go buy your friends a round. Come back in the spring.
9) Apply Interlux 2000e (2-part) barrier coat as desired. I like a couple thick coats (see hint).

Hint: cover any unused barrier coat to keep it from evaporating. Use it the next day as-is or mix more into the old, now-thicker batch. Even though it's 2-part, it doesn't seems to work by chemical reaction like epoxy but more by evaporation like normal house paint. More hint: if using a mixing cup from West Marine, grab it from the top -- like a bad waiter in a restaurant -- and peel your Nitrile glove off you hand and right over the top of the cup, sealing it. Put it in the shade. That's all you need to do, to use the remainder the next day. It will be thicker, but thicker is good since it's not how many coats you apply, but the eventual thickness that counts.

10) Follow all timing when putting bottom paint over barrier coat. Generally (from memory) bottom paint goes over barrier coat only before the barrier coat is fully dry. That means hours. And barrier coat goes over barrier coat within 2 weeks, otherwise sand between coats of barrier coat. (You will need to apply more barrier coat if you didn't get the bottom paint on while the barrier coat was not-fully-dry.)

That's it! So simple. No grinding, less mess, an less timing stress.

Hope this helps. It's made a huge difference to me.

Regards,
Brad


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## krisscross (Feb 22, 2013)

Sounds simple and very practical. Can it be used on steel hulls as well?


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## JimsCAL (May 23, 2007)

Brad is back!! Still keeping the boat out in Montauk?


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## Jeff_H (Feb 26, 2000)

One Quick comment: 

I have become a huge fan of PetitProtect barrier coat instead of the Interlux (Interprotect) 2000e. I found that the Interprotect required way too many coats to build up a reasonable thickness. The Petitprotect builds much faster, and requires way fewer coats. Petit claims better impermeability and adhesion, but I can't attest to that. 

The Petitprotect goes on slightly more texture, but that may only be my technique, and using the wrong roller (I need to experiment with that) and so may not be a problem with the material itself. I typically build up all the coats up that are required except the final coat and do a light sanding to remove any texture. The Petitprotect seems to be easier to sand smooth before the final coat and with its greater millage does not seem to have locations with 'thin spots' where you can see through to the base materials which has been a problem with the 2000e that has lead me to apply additional spot coats. 

Jeff


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## smackdaddy (Aug 13, 2008)

Bene, baby! Good to see you dude. And thanks for the great update!


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## Minnewaska (Feb 21, 2010)

Good to see you back, Bene. Where ya been? Hoping you've been sailing your bottom paint off.


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## Bene505 (Jul 31, 2008)

Yes, on the boat now. Gray and rainy. Stepped up marine patrols here. They got a super fast inflatable from the state -- must be like a $200K boat -- and they are giving out tickets -- mooring permits to stay here, frequent holding tank checks. Nice guys, just enforcing everything.

By the way, long range wifi replaced by Verizon unlimited HotSpot on iPhone. 

Regards,
Brad


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## Bene505 (Jul 31, 2008)

Minne,

Been sailing, not really online much. Kids growing up. And working my tail off -- work plus my "side hustle" of the Hatch Dorade invention. Has kept me busy. Got my captain's license a year or two ago. Still very much in it, just less online.

It's great to be back on and seeing all the familiar avatars. The pirate flag thread is still active. That's amazing.

Where is Mark now?? Did he ever cruise with a hottie or still solo on the big hops?

Regards,
Brad


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## miatapaul (Dec 15, 2006)

Welcome back! Seems like Sailnet is coming back to life again. Seemed to be pretty slow for a while. We should meet up when I get back to NY. (am back in Midwest due to family health issues) So the poopinator invention is not making so much? I have done some sailing on the southern sound with a friend and have been living aboard for a year and a half now. 

Mark is in the Med this summer, not a bad place to summer!


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## CalebD (Jan 11, 2008)

Hi Brad,

How are the four heads on your boat doing? I remember them intimately.
Where is all this stepped up marine patrol stuff happening ? Montauk harbor ? aka Lake Montauk.

It is July so "Summer Boost" should be in Montauk or points east.

Regards,
Caleb


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## Minnewaska (Feb 21, 2010)

Bene505 said:


> .....Where is Mark now?? Did he ever cruise with a hottie or still solo on the big hops?.....


We just assume they were hotties, no pics. Just had two along from St Martin to the Azores. He may be more of a gentleman than he would like us to believe.  Then again, they took a flight the rest of the way, so we can fill in all sort of reasons and Mark ain't talkin.......


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## midwesterner (Dec 14, 2015)

I can't see the photos. Thought it might be my phone but got on a real computer and they still don't come up.


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## midwesterner (Dec 14, 2015)

I cannot see the photos on this thread, Trying to right click on the photo icon and choosing "Open in New Tab" only takes me to a page that says "Page Not Found".


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## Bene505 (Jul 31, 2008)

Midwesterner,

I don't think the photos matter anymore. My new procedure involves wire brushing without any grinding. I'd just follow the new written guidance.

Regards,
Brad


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## midwesterner (Dec 14, 2015)

Bene505 said:


> Midwesterner,
> 
> I don't think the photos matter anymore. My new procedure involves wire brushing without any grinding. I'd just follow the new written guidance.
> 
> ...


I was still curious to see the photos of what it looked like.

I don't ever intend to own a boat with an iron keel, regardless of what is the best way to fix it.


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## chef2sail (Nov 27, 2007)

Good to see you Brad🤘🤘🤘🤘😄😄😄😄


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