Mailport May 15, 2000 Issue

Mailport 05/15/00

Foss Foam Rudders
In reference to your article on rudder repair I would like to add the following. Since the 1960s the Foss Company in Costa Mesa California (949/646-0244) and Foss Foam in Clearwater, Florida (727/571-3626) have been making foam core rudders. We estimate that between the two facilities we have produced more than 40,000 rudders. Some of the builders we have produced rudders for are Hunter, Cal, O’Day, Columbia, Ericson, Endeavour, Ranger, Morgan, Lancer, and WD Schock.

Our method of construction is significantly different than the rudder that you repaired for your article.

Foss Foam Rudders have a foam core made of 24-lb. per cubic foot density close d-cell polyurethane foam. The strength of the rudder is the steel framework (typically a 304 stainless tube/bar with a mild steel plate attached) and the high density foam core. The fiberglass shell is more cosmetic than structural.

The number one area of trouble with foam core rudders is delamination. When we manufacture a rudder we do it from the outside in. Rudder molds are like a clam shell with a dividing line right down the middle. The gelcoat goes on first, then the fiberglass is laminated on top. After the fiberglass cures, the rudderstock or steel is laid in the mold and foam is poured in. The mold is closed and foam expands to fill the cavity.

Our rudder molds are heavily constructed as the foam gives off tremendous pressure. After an overnight curing process the rudder is removed from the mold, the seam is ground off and glassed then sprayed with gelcoat again. All production takes place in a timely fashion so that a chemical bond occurs. Before the rudder is bottom painted it should be sanded lightly to remove the mold release wax. Applying a barrier coat is a good idea.

We recommend that a light color bottom paint be used. In tests conducted at our facility in Clearwater, dark color bottom paints reached temperatures ranging from 160°-190° even on winter days. These temperatures cause gasses to release from the foam. The gas pressure delaminates the fiberglass from the foam, thus causing a voided area between the fiberglass skin and the foam. Over time, water will penetrate and eventually may delaminate the entire skin. If you must paint your rudder a dark color, the easiest remedy is to shield it from the sun whenever your boat is hauled. Damage may occur in less than one hour.

Secondly, check your rudder yearly (or whenever you haul out). Check for electrolysis or any problem with the shaft. Even a slight bend can spell big trouble down the road. You can tap on the side of your rudder with a large metal washer to sound out delaminated areas. If you catch them early (the size of a baseball) you can drill a hole at the top and bottom of the voided area and inject it with resin. If the voided area is larger than 6" in diameter then the delaminated area should be cut away, left to dry and glassed over. If the rudder will not dry you may need to remove more material or have a new rudder made on your existing rudder stock/steel.

Dealing with the factory is less expensive than most people expect. For example, off-the-transom rudders cost from $300 to $700. Prices on rudders with a rudder stock/steel start at $700. Many times you can buy a new rudder for less than the cost of a repair.

The other program we offer is to rebuild rudders. We take an old rudder, strip off all material down to the stock and make a new rudder on the existing shaft. The cost is about 60% of the price of a new rudder. Prices are for models for which we have the mold and do not include freight. We have over 300 molds in stock.

Every boat owner should make a detailed drawing of his/her rudder to keep on file. For owners of boats with off-the-transom rudders this is particularly important as we are contacted regularly by owners who have had their rudders stolen. Having this information saves time, money and the chance for mistakes when ordering a new rudder.

Bob Walker
Foss Foam Products
4480 126th Ave. N.
Clearwater, FL 33762

Inexpensive Alternator
Last spring I did some work on my uncle’s 28' Hunter. He wanted to live aboard and all manner of electrically thirsty devices were added. I determined that the low-output alternator that came with the Yanmar would have to be run ad nauseam to keep up with the demand of the overall system(s).

A replacement was needed and it fell on me to determine which one to install. When I priced marine alternators I thought the supplier was having me on. In addition, they required, according to him, an external “smart” regulator.

“I don’t think so,” I mumbled to myself.

So, I went up the street to our local auto supply house and spoke to Old Bert who I knew well and who has been in the auto-electric business since just before Herr Diesel was born.

“Yep,” he said. “Know what you’re after. Off a school bus, she is.”

We searched through the books and decided that a Delco-Remy part #A1358 would do the job.

“And the regulator?” I asked.

“Don’t need one,” he replied. “She’s built right in. Just attach a heavy wire from this here terminal to the positive side of the battery.”

It took a few minutes, perhaps an hour, to get the new alternator installed. I had to run a drill through the mounting boss on the engine, about a 1/2 mm larger, and do some filing in the adjusting bar. It took some time to run the wire (I wanted to leave the original wiring in place in case we had to put the original alternator back on) and the rest of the afternoon to get the pulleys sized the way I wanted them and lined up perfectly. I decided to use a ratio of 1:1.9 or so. 1:2 is not a good idea because of potential wear patterns. A new belt was needed, but that was right off the shelf.

Here are the results. The output of the new alternator at 1000 rpm engine speed, is just over 100 amps. At 2500 rpm the alternator is cranking out 135 amps. At full song, which doesn’t bother the alternator at all, we see just under 150 amps. You can imagine how that cuts down on the running time of the engine.

It ran that way all last summer around the Montreal area (sailing more than motoring) and then it took my uncle and me up the St. Lawrence river, across Lake Ontario, through the Erie Canal system and the Hudson river (motoring 10 hours a day) and as far as Atlantic City where I got off the boat to come home and he continued on. It ticked merrily along all winter and made the return trip to Montreal. When I asked Uncle Donald about the alternator he seemed surprised I would ask. “Why, perfect,” he replied.

I guess the thing still thinks it’s on a school bus, happily motoring through the rural roads of Canada. Only in the summer time.

Barry Webb
via e-mail

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