Cast iron keels and keel bolts

Before..

...after sand blasting, epoxy filling and sanding, then three coats of epoxy primer the cast-iron keel of our Columbia 43 is ready for bottom paint. It has a complex and beautiful shape that you could only achieve with a strong, durable materal like iron.

I get a lot of questions about keel bolts. Almost every potential owner and owner of a Columbia 43 worries about them.

I only really know about my boat, a Columbia 43 Mark I, but I think it is like most of Tripp-designed boats Columbia built. They had cast-iron keels attached with galvanized keel bolts. The keel was set in a socket in the fiberglass hull with an industrial adhesive called Furane Epibond, which is still made today.

The keel installation page from the Columbia 43 plan set. Note the beautiful drafting, which was all done by hand. Tripp was a consummate artist.

Here's an interesting paragraph from a 1971 article in Boating Magazine describing in detail how the keel on a Columbia 43 is attached:

"With a 10,250-pound cast iron fin keel hanging on the bottom of the boat, we were interested in the method used to secure same. We found that the keel flange is flushed into a recess or pocket in the hull. Prior to attachment, the keel is given a dry run to check for accurate fit in the recess. If all is not well, the flange is ground to suit--the pocket is never ground except to remove gel coat. When the fit is satisfactory, the recess is coated with a thick application of Furane Epibond, and epoxy compound. With the entire weight of the boat resting on the keel, ten 3/4" diameter cotton-wrapped bolts, nuts, flat washers and lock washers are installed. Internally the keel weight is distributed by a heavy, glassed-in platform and a series of steel transverse channels that pickup the keel bolts. We were convinced that the keel is there to stay."

The article didn't specify that the bolts were galvanized steel, but the plan sheet for attaching the keel does. That's what is on my boat too.

Galvanized bolts were exactly the right thing to use. They start out being 18 percent stronger than the same sized stainless bolt. From there the stainless bolt has nowhere to go but down. I would not trust any stainless bolt more than 10 years old. They can look perfect and yet fail catastrophically with no warning.

Galvanized bolts, on the other hand, retain their strength even when they are rusty. So a 50-year-old galvanized bolt that is 18 percent rusted away is about the same strength as a brand new stainless steel bolt. I won't even get into crevice corrosion in stainless steel. Let's just say a damp bilge provides the perfect environment for crevice corrosion.

If someone, I'm thinking a boat buyer here, looks in a bilge and sees some rusty keel bolts they totally freak out! I've had more than one person tell me that they once considered buying a Columbia 43, but didn't because of the condition of the keel bolts. I also had a C-43 owner bemoan the fact that she almost had her boat sold until the potential buyer looked in the bilge and saw the keel bolts. I told her to get a wire cup for her drill and go to work on them to get the loose rust off them, wipe them down with acetone, prime with a rust converter and then spray paint them white. I hope that was good advice. (While you're at it GET RID of all the old useless wires, pumps and junk in the bilge.)

The keel bolts on the Columbia 43 Mark I were studs and can be backed out (theoretically). I wouldn't do it. I might sister them, but I would not do that either unless the bolts -- all or most of them -- had all but disappeared. I can think of all kinds of things that could go wrong. You could get the new bolts torqued wrong and start a leak, for example. (More about this later.)

The thing is, there are no cases where a Columbia 43 has lost her keel. If there were, we would hear about it. (Think Cheeki Rafiki.) Also, Columbia tested the adhesive system they used on these keels using it alone without any keel bolts. It worked fine, or so the story goes. I don't know if they went back and added keel bolts later or not. Let's just say I trust my 46-year-old keel attachment more than I would most new boats.

Now for the Columbia 43 Mark III: The Mark III was a later development of the original Mark I. One of the biggest changes Columbia made was a smaller keel (same depth, 6'11", but a much shorter chord) to reduce wetted surface. I haven't seen a Mark III out of the water nor have I seen the design drawings. From what I can gather the keel had external lead ballast on a fiberglass keel stub. I don't know what kind of bolts they used. I also don't know who did the redesign, since Bill Tripp (the Columbia 43's designer) was dead before Columbia came out with the Mark III.

One of my friends who has a Mark III in the Sea of Cortez had problems with his where it developed a smile (in boatyard parlance, it's called a "Catalina smile"). It looked like the keel was starting to become detached. He had a yard in Mexico fix it -- I don't know the details -- but so far he's happy with it.

Stumpy J, the Columbia 43 Mark III that competed in the 2013 Transpac and finished 6th in Division 8, the same division that Dorade won that year, also had problems with her keel. When the owner was getting her ready for the race someone recommended that he re-tighten the keel bolts. He did that and it caused leaks that plagued the boat throughout the race and afterward.

That's about all I know about Columbia 43 keels. I believe a lot of the Tripp-designed Columbia's had cast iron keels similar to the 43 Mark I. One notable exception is the Columbia 50, which has lead encapsulated in the fiberglass hull. (This, to me, is the most trouble-free method. I hesitate to say "best" because other things come into play.)

I generally think Columbia 43 boat owners worry a lot about keel bolts because they look bad, not because there is any real danger of losing a keel. Should I be worried? Comment below. You'll have to cite actual examples of keel failures if you want me to pay attention.

Differences between Columbia 43 Marks

Columbia produced three versions of the Columbia 43: the original Mark I, a keel-centerboard version called Mark II and, after 1973, a Mark III. There's a lot of myth and misconceptions about the differences, especially between the Mk I and Mk III. I hope to cut through most of this.

Differences by the numbers

The following information came from two Columbia brochures. One is likely for the original model, which was offered as with a fin keel or with an abbreviated fin and swinging centerboard. The MkIII specifications came from a general Columbia brochure (circa 1974) which included the C-43 MkIII.

                      KEEL         KEEL/CENTERBOARD     MkIII
LOA                  43'3"            43'3"             43'9"
LWL                  32'8"            33'0"             32'8"
BEAM                 12'4"            12'4"             12'4"
DRAFT                 6'11"       4'11"/10'3"            7'0"
DISPLACEMENT         22,200           23,500            22,200
BALLAST              10,300           11,600            10,300
SAIL AREA           810 sq ft        810 sq ft         852 sq ft
OPTIONAL POWER              Palmer M60                 50 HP Perkins 4-107 Diesel
WATER                48 gal           48 gal            50 gal
FUEL                 50 gal           50 gal            50 gal
VERTICAL CLEARANCE   58'4"            58'4"             64'4"
DESIGNER Wm Tripp

Keel differences 

The big difference between the three Marks is in the keels. The Mark I has a cast-iron keel with an intricate shape when viewed from fore or aft. The Mark II has a keel stub, which houses a centerboard. The Mark III has a fiberglass and lead keel the same depth as the Mark I, but with a much shorter chord (the length between the front of the keel and its aft end).

A Mark I keel viewed from the stern.

The Mark I cast-iron keel has a beautiful shape that could only be achieved with a strong, heavy material like iron. It is narrow close to the hull to create a more hydrodynamic shape and then flares out near the bottom to put more weight lower increasing its leverage.

Mark III. Notice the shape of the keel and the skeg-hung rudder.

The designer of the Columbia 43, Bill Tripp, Jr., was rightly famous for his keel-centerboard designs, so you would expect that as an option. Of the three Marks, the Mark II is the most rare. It is also 1300-pounds heavier than either of the other two. I don't know how many Mark IIs Columbia produced, but I have never seen one offered for sale. I imagine the Mark II was somewhat more expensive than the Mark I. Unless shoal-water capability was critical, most owners would skip the extra initial expense and the added maintenance. The keel is the only difference between the Mark I and the Mark II.

When the Mark III came along in 1973 (four years into the production run) it had a new keel with lead ballast and a shorter chord. The lead ballast was necessary because the keel was smaller, which gave it less wetted surface. It also put the ballast lower to accommodate the six-foot taller mast with its higher-aspect rig and 5 percent more sail area.

Rudder differences

Standard Mark I and II rudder.

The optional, skeg-hung rudder on a Mark I looks different
 from the Mark III.

The Mark III rudder was redesigned as well. Instead of the scimitar-shaped balanced spade on most of the Mark I and II models, it has a skeg-hung rudder. I say "most" of the Mark I and II boats because Columbia offered a skeg-hung rudder as a option for the earlier models. Some owners of these boats assume, because it has a skeg-hung rudder, it is a Mark III. It ain't necessarily so.

Bow differences

The Mark I bow on my boat Oceanus.

The bow on the Mark I and II sweeps upward in a beautiful line typical of Tripp designs until it gets to within six inches of the deck, where it goes vertical at the hull and deck joint. I don't know why it was designed and built this way. It could be to keep the boat a half-foot shorter and thus make it rate lower under the CCA (Cruising Club of America) rule, or to make the hull and deck joint easier to build. For whatever reason, the beautiful line of the bow looks broken at the top.

The Mark III carries this line to its logical conclusion, thus lengthening the base of the foretriangle (and the total length of the boat) by six inches. While this improves the aesthetics of the boat, the real reason was to increase headsail area, thus making the Mark III more competitive under the new (at the time) IOR (International

The bow of Magic Woman, a Mark III based in Monterey, Calif.

Offshore Rule). Which brings us to...

The rig

The rig on the Mark III is closer to an early IOR rig than a CCA rig. The headsail area is larger because of the six-inch extension of the bow and a six-foot taller mast. Columbia shortened the boom on the Mark III to give the mainsail a higher aspect favored by the IOR rule. The total rig change increased the sail area of the Mark III from 810 square feet to 852 square feet, or about 5 percent. The lion's share of the increase was in the foretriangle.

Different deadlight

Distant Dreamer, a Mark III based in Japan, shows the two portlights on the cabin sides.

The Mark I and II had the trademark long Columbia deadlight on the 43's small, gun-turret-style house. Most, but not all, Mark IIIs have two smaller rectangular opening portlights on each side.

What remained the same?

Just about everything: Same deck layout, same interior, same construction methods (except for the lead keel), same hull shape, same headroom, same cockpit configuration, in short, all the things that made the Columbia 43 the best selling of Columbia's big racing boats.

Conclusion

Encore heading for the finish in the 1971 Transpac Race where it was the overall winner.

Columbia wanted a great race boat when it commissioned Tripp to design what became the Columbia 43. Specifically, Columbia wanted a boat that could win the Transpac, which starts in Long Beach, Calif., and ends in Honolulu, Hi. That's exactly what they got. In 1971, Encore (a Mark I), won her class in Transpac, and was eighth overall in the fleet. In 1973, after the IOR replaced the CCA as the official rating rule, Columbia introduced the Mark III to keep the model competitive a little longer.

Now that most sailing competition is handicapped under the PHRF (Performance Handicap Rating Formula) the boats are again winning silver. The Mark I has a PHRF rating of 102 and the Mark III has a rating of 96.

Which of all the three models makes a better boat? It depends on its intended use. Since most Columbia 43 owners use their boats primarily to cruise I would venture to say the Mark I gets the nod because of its smaller headsails, shorter mast and the longer, stronger keel. But many owners love cruising in their Mark IIIs. All three variations are on the mark.