Final keel cooler installation and beginning piping

So I got the third keel cooler for the future generator (see my previous post on finding this on Craigslist) in the recessed box in the hull! I had to wait to get the 3M 101 polysulfide sealant that is recommended as my local boating store was out of stock. Once this cooler was gooed in and bolted tight, it was time to get the guard on that I had sitting up on deck for the last year. I built this guard out of 1 1/2 inch solid round bar that I had left over from making the stanchion posts. I painted it and the box with a few coats of black antifouling paint:


Thanks to my brother, Tim Fischer, for the gift of the 3/4 inch 316 stainless bolts and lock nuts. He got these for me for my birthday last year and I have been waiting ever since to use them on this project.

Here are some pictures of the recessed box when it was being made many moons ago:

Roll 2 - 1765

Roll 2 - 1830

Since the inlets and outlets for the keel coolers are now known inside the boat, I have started to run the piping for them. The connections to the GM 6-110 diesel engines are 2 1/2 inch and so are the connections to the keel coolers, so it only makes sense to run 2 1/2 inch piping. This is also recommended by Fernstrum, the company that makes the coolers, to maximize the coolant flow through the system. The one hiccup, is that my pipe threader only threads up to 2 inch pipe, so I have had to order 2 1/2 inch fittings that are the butt weld type. So each fitting is going to be welded on, which takes a bit more time to do.

Here is a picture of one of the first finished sections after being welded and awaiting sandblasting and primer:


Where the piping meets the engine, I have flexible high temperature silicon hose adapters and I have left a 2 1/2″ threaded tee with a threaded plug near the engine. I used a threaded tee so that I can possibly remove the plug and add a modine heater in the engine room at some later date. I also welded some 3/4 inch threaded weld-on pipe fittings so that I can add a temperature gauge, a temperature sending unit and a thermal expansion tank.


I am installing these pipes under the engine room deck plate to keep them out of the way. As some of the piping runs are kind of long (and heavy!), I am using weld-on steel flanges to join the piping sections together.

Note to self – I need to calculate the volume inside the piping, keel cooler and engine to be able to get the right sized expansion tank and enough antifreeze….

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  1. Posted January 6, 2010 at 12:20 am | Permalink

    What kind of antifreeze are you going to be running in the system? I have heard of several of them out there other than what we use in autos. I am not sure what exactly to use.

    By the way nice job on the coolers.


    • Posted January 7, 2010 at 8:31 am | Permalink

      Hi Dave,
      No – I haven’t worked that out yet. Any suggestions? I’m not sure why regular auto type antifreeze would be bad? Maybe because it sits for awhile and isn’t circulated as often? As I am running black steel pipe between the engine and the keel cooler, I was thinking of adding some sort of anti-corrosive additive. Any advice?

      • Posted January 11, 2010 at 10:04 pm | Permalink

        Ok I am sorry that it has taken me so long to reply. I have taped into my long list of contacts. Tim, one of my best friends in the world is a U.S. Coast Guard licensed Chief engineer, Any ship any tonnage any form of propulsion. I spoke to him this evening and he said you want to use maxiguard. Not Automotive antifreeze. He also gave me some advice to pass on to you. Have the Craigs list Keel coolers hydro tested before you go back in the water.

        I have asked him to post on your blog. He is a great person for information with any question, I don’t play trivia pursuit with Tim.

        He does not have his computer this evening but he will be on your blog tomorrow.

        I hope we can help. Someday I would love to see your ship.


        David P. Gill

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