KEEL ALTERATION
Submitted by Tim Davis
“Gale Force II”

Some of the PYC members are aware that I altered the keel on my 1987 Hunter 40 in the spring of 2006. Since I have had so many people inquiry about the whys and wherefores I will share my experience with the club.

I won’t go into all the reasons why we decided to buy another Hunter 40 after the previous one burned. The only difference between the two models was the keel configuration. The former was a 41/2 foot shoal draft and the later was a 61/2 deep fin keel. I bought the deep draft knowing that I would need to shorten the keel if I planned to continue my tenancy with Dan’s Pepin Marina. I had seen several 6 foot draft boats hung up in the marina. Any slight doubt I may have had went away immediately when I came into DPM on Labor Day 2005 and went aground trying to tie up to the transient dock.

During the off season of 2005-6 I researched keel shortening and quickly concluded that the “go to” company was Mars Metal Co in Canada. I told them I needed to shorten the keel by 12 inches. They have software that once programmed with information about the boat model and keel configuration will calculate the amount of replacement weight to keep the same Righting Moment. Hunter Marine had long ago discarded the information about my keel model so I had to provide the statistics needed by Mars. This I did following their instructions. Mars told me that cutting a foot off the iron keel would remove about 700 to 750 pounds of weight and that I would need to replace 1000 pounds of lead (in the shape of a torpedo). I placed the order before the price of lead rose.

I do most maintenance on the boat myself, but shortening the keel and adding replacement weight was a job for a professional. After looking around and consulting with Mark Lutjens in Lake City Marina I decided to hire a Lake City metal fabricating company. Mark agreed to allow me to “hang over” Easter weekend which gave us four straight days in the Travellift. The metal workers tried several cutting strategies but settled upon a carborendum blade chop saw as the most effective tool. They scribed a line parallel with the water line and went to work. They ground a groove around the keel which they then followed round and round taking half inch bites at a time. It took nine hours of tedious grinding and 14 blades before the 700 plus pound ingot dropped to the ground. The cut was remarkable smooth and flat. Ron looked at me with relief and remarked that the worst was behind him. Little did he know…

The next step was to drill five 1” holes horizontally through the keel that matched the predrilled holes in the “torpedo” halves. That might not seem like a big job but just imagine drilling through cast iron, with thicknesses varying from 1 inch to 8 inches, and having holes line up when keel surfaces are curved and not at all perpendicular to the hole. Ron selected a magnetic drill and shimmed it up to allow a perpendicular hole to be drilled. The drill has a powerful electromagnet that holds it on the keel so the operator need not hold it in place. Even better it has a mechanical crank that forces the drill bit into the metal at glacial speeds. Seeing that machine in operation and knowing that cast iron is relatively soft I thought the holes would be punched through in short order. No such luck! Apparently when the Iron Brothers in England cast the keels they threw anything and everything into the melting pot. Ron soon hit extremely hard spots where the drill simply would not go further. He tried sharpening the bits often and he tried better quality bits to little avail. Progress was extremely slow. Finally he turned to super hardened carborendum bits to finish the job.

When the holes were finally drilled Ron lifted the “torpedo” halves into place with floor jacks and ran the 5 bolts through the holes he struggled to drill. Both inner sides of the “torpedo” halves were coated with thickened epoxy to provide a water proof sealant between lead and iron. The bolts and their nuts were tightened with a torque wrench and “Voila!” the torpedo bulb was securely bolted in place. The last step was to apply more thickened epoxy around the joint where lead met iron so that no water enter and cause rust. I then faired the bulb with epoxy and Microlight and finished the job with several coats of barrier and bottom paint. The finished product was very professional and even beautiful!

Now came the “acid test” to see if the righting moment was adversely affected, and if the boat would point as well as it did before the keelectomy. I sailed Gale Force” all 2006 season and could not tell that any alterations had been made to her other than that I had no groundings. Thanks to Mars Metal Co and the Lake City metal fabricators the keel alteration was a big success.

this site maintained by beth anderson of plum creek associates