Rusty Ballast – Surgery Deep in the Heart of an H28

Jun 30, 2018 | Technical

Being the proud owner of a Compass Yacht built Herreshoff H28, I would like to share with other H28 owners an experience I had with my boat, Centesimal, during the winter of 2000.

The Problem: Early last year, I noticed all was not well with the keel. A problem I had read about (and hoped never to encounter!) was in fact present. Water from the bilge was entering the keel via a poorly built bulkhead just forward of the engine. The steel punchings that make up the ballast had become badly corroded, and as a result, had swelled and were pushed out through the fibreglass. Splits were clearly visible on the outside of the keel The punchings in the bottom third of the keel had understandably deteriorated the most, and formed a solid (but growing!) mass of rusted metal.

The Preparation: Before attempting the repair, I sought the advice of local boat builders and yachties, but could find no one who had fixed one of these problems. I was going to have to “Make it up as I went along.”

As I live by an estuary, it was a relatively simple process to have a crane lift the boat from the water, and place it in a cradle on my front lawn. Once the boat was in place, my son Philip and I made a start I could see it was going to be a very dirty job, so the first thing we did was to strip all the gear from the boat’s interior. To gain access to the keel, I used a skill saw to cut around the plywood floor, about 50mm from the bunks, doors etc. To tie the side of the hull together, the top of the keel had a thick layer of woven rovings and fibreglass. To get to the punchings beneath, this had to be removed by cutting into squares with an angle grinder (this proved to be one of the hardest jobs as the resin had bonded with the top layer of punchings).

Out with the Old: We could now commence the process of breaking up the rust, steel, rusted steel, resin etc. This was a slow, dusty job and resulted in more than a few bleeding knuckles! We started at the engine (aft) end. This was the easiest “entry point” as this was where the corrosion was worst (and therefore the metal relatively soft). After experimenting with a variety of tools, I found a sledgehammer to be most effective against the top layers, where the punchings were still in good condition. Lower down, not only did the corrosion increase, but the punchings became interspersed with smaller objects such as nuts, bolts and even bits of wire. To break up this stuff I used a small air chisel. The old ballast was removed with garden trowels, 10 litre paint pails, and a hell of a lot of sweat. I ground and sanded the inside of the now empty keel to remove the last of the rust and the few punchings that were embedded in the fibreglass. To finish off I thoroughly cleaned away the dust, and the oil and bilge water that had penetrated the full length of the keel.

The pictures above shows the removal of ballast from another H28

In with the New: I set about restrengthening the keel by adding three bulkheads. Placing one in the same position as the original, a second forward (under the saloon bulkhead) and the third half was between the first two. Whereas the original bulkhead was of relatively thin plywood, kept in place by glue around its edges, I covered the new ones with multiple layers of fibreglass, then glassed them into position. These new bulkheads would have saved the Titanic!  For added strength, I placed strips of double layer fibreglass, about 10cm wide along each side of the lower hull, ie where the hull curves to form the keel. The keel was now ready to receive the new ballast. As per the boat’s specifications, the new ballast had to weigh 1800kgs. I achieved this by using 1200kgs of lead ingot, 500kgs of cement, and the remaining 100kgs being made up of fine crushed gravel and two drums of Nuplex Polyplex 3001. We placed the ingots in single layers along the full length of the keel, using the gravel chips to fill the gaps. The Nuplex was then poured in to form a solid layer. We repeated this process until all the ingots had been used. At this stage the ballast reached two-thirds the way up the keel. Realising that I had a lot of space with the heavier lead, I decided not to go to the expense of purchasing the last 500kgs of ingots, simply finishing the job by pouring in concrete to the same weight (even with the concrete, there is still a 75mm gap between the floor and top of the keel).

Once the floor was put back, we could say the job was finished. The inside of the boat however, was a hell of a mess! Punchings, fibreglass sanding dust and rust had gotten into every place possible. While Centesimal had been out of the water, we also gave the outside some attention, giving it a completely new paint job, replacing or renovation suspect fittings and woodwork, and replacing the milky perspex windows with ones we could actually see through.

Thoughts: now that the job is done, I am very pleased with the results. The boat feels the same as it always did, the there appears to be no change in its handling characteristics. Recently, at an H28 race series held in Nelson, Centesimal performed very well, achieving a straight run of second places. I am happy that I now “know” what is in my keel, and to enable checking periodically, I have fined “lift up” sections to the floor. I do not like places in a boat that ate sealed off at the time of manufacture 20 plus years is a long time to never be able to check for water, cracking, rust or whatever! Since the bulkhead forward of the engine was the source of our problems, I recommend that other H28 owners check theirs. The H28 is a great boat for the money, especially when compared to the price of other yachts today. I have looked around many of the country’s marinas, and noticed many good examples of the class. Some others are starting to show their age, but like my boat, I am sure they would respond well to a bit of TLC. Certainly, Centesimal has a lot of sea miles in her yet!

Happy Sailing.

Robert Stebbings- CENTESIMAL