Making Keel Cooling For A Friend

A very good friend of mine had a new engine fitted recently.  The boat was an ex hire boat and only had a 35hp engine which is fairly normal for a hire fleet boat. The hire companies do this deliberately as they want to control the speed the boat can achieve and they probably govern the engine as well.

The beauty of these boats is they can be bought for very reasonable price, they come well equipped with quality fittings to stand the riggers of hire and the hulls are well built.

So the internal skin tank was set up for a 35hp engine, a fact the professional boat company installing the new 52hp engine somehow overlooked?  Hmm?! IMO the first thing to work out when fitting an engine is how to cool it.  If you cant cool it you cant run it.  Well you can but so long as you dont call up all the horses or want to destroy it. 

The problem only manifested itself when Sue needed to punch against the flow on the Thames, which of course needed more horses than poodling on a canal which she had been doing since the new install.

There were 2 options to solve this, another internal skin tank linked to the original which would require the engine bay to be cleared of things like the errr! engine!  The other option an external skin tank, or keel cooling which is really what a skin tank is requiring just 2 holes made and welded in the hull.  No engine removal and just a few hours work in a dry dock.

Theres a well regarded formula for working out the cooling area / engine hp.  Its HP divided by 4, so a 52hp engine needs 13sq/ft of surface area.  The most compact way of doing this is with tube, in this case 80 x 40 box section which gives 1sq/ft of surface area every 16" of length.  To further compact this a serpentine patten is the norm.

This is it.

So this is what I came up with and made for Sue & Vic.  See the links below as she takes up the story on her blog.  Read backwards from here:-  Sadly I wasnt able to fit it for her, but the local floating dry dock did a great job.

If you like boating blogs, you will love Sues.  Hers is constantly ranked in the top 10 UK boating blogs, its has a great balance of travelogue, opinion, and lifestyle showing the good and not shy of speaking about the not so good. Always punctuated with great photos and on the sidebars masses of excellent links, tutorials and resources as well as a massive list of fellow boater blogs.

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Hello Old Friend!

Yesterday I got out to the boat shop after over a month of  running around with the trailer, the new job, and starting graduate school full-time. Luna looked so sweet and lovely as I approached the shop. I climbed up on her keel, situated myself where her "cockpit" will be and lingered for a few moments imagining rolling waves instead of rolling hills. Then I got to work building the L-A-S-T frame! More on that tomorrow.

View from Lunas cockpit.

One thing Ive learned about boat building is that the shop needs to be a pleasant place to work. This doesnt necessarily mean lots of expensive tools (Im still a proponent of using the cheapest functional tools you can get), nor does it mean a climate controlled, deluxe barn. I guess to me it just means less exposure to the elements. The shed I work out of, while the price is right, has a dirt floor and only one wall to the North which makes exposure to all sorts of stuff inevitable.  

A project like this requires thousands of hours. Given this, it is generally best to limit the "excuses" one has to not go out to work during a few spare hours. Sometimes I find myself hesitating to go to the shop because it is 110 degrees outside, or the wind is really high and I dont want to cough and sputter in the heavy Texas dust. I am no delicate petunia, but sometimes thats just a bit too much. 

View of the shop floor.

While I have been less-than-organized all my life, this mess is not all my fault. Let me introduce you to the beautiful part of the USA I call home:

It isnt quite this bad.

Actual view from the back of the shop.

When I moved here a couple of years ago, the ranch was lush and green:

The ranch in September, 2 years ago.

Then the drought hit and we havent had much rain since. This, combined with the common practice of ranchers in my area desperately clearing the land of all vegetation on the false hope that it might rain (it never does), means it is pretty dusty here. 

While the ridiculous amount of dust might drive me to entertain apocalyptic thoughts, I cant imagine what its like for the ranchers whose livelihoods depend on the rain. My heart breaks to see the hardworking couple who own the ranch I live on sit on the porch praying for rain as thunderheads roll in-- and then roll out-- without a drop of water hitting the ground. Heres to hoping the drought ends soon.

Boatbuilding in Hindsight
Boat shop requirements for The Next Boat:

1. no months average temperature may exceed 100 degrees Fahrenheit 

2. the shop must have at least 5 sides (one of these must be a roof)

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