___ M26C Weather Helm___
The Macgregor 26, which was made from 87 to 95, is a fine sailing boat. It is the fastest boat that Macgregor has built. (Not counting the catamaran or the 65.) Even though it is a trailerable boat with water ballast, the M26 is faster than most of the boats in its size range. The boat does have one bad characteristic. When hit with a puff she will develop more force to turn into the wind than the rudder can control and she will round up. This is not only annoying it can be dangerous if there are other boats or obstacles close by.
The problem is more severe in the 88 and 89 M26's because they have daggerboards. The swing centerboard models built after 89 can reduce weather helm by pulling up the board a little.
A boat should be tuned, by adjusting the mast forward or aft, so that in a five to ten knot wind the boat will just have a little weather helm. (It should slowly head into the wind when the tiller is let go). When tuned this way, the MacGregor 26 has the mast just slightly raked aft. The problem is that when the wind increases the healing also increases and the rudder becomes inadequate for the job.
Reducing the healing forces is the first thing that should be done when the healing increases. The mainsail should be as flat as possible. The halyard should be very tight. The out haul should also be tight. Reefing should be considered. I found that on my boat the mainsail got fuller as the sail got older. It took recutting to return it to its original shape. Most Macgregor mainsails have only one reef point (what is called the second reef) in the main. It pays to have two reef points (add first reef) so that sail can be reduced in small increments. It is when you are overpowered that the helm becomes a problem.
The 88 and 89 boats have the rudder mounted on the transom. The aluminum part of the rudder is made so that under twisting forces there is a lot of flex. When you pull the tiller it moves more than the rudder. This leads to a mushy feel in the tiller. There are two ways to correct this. One is by welding an aluminum plate over the back edge. This plate should be put near the top so that it won't interfere with the raising of the rudder. A plate 6" tall will do the job. The second way of stiffening it is to bolt a piece of wood in the channel. A piece about 8 inches long works well. Again, it should not interfere with the rudder going up and down.
The next modification (needed on all the boats 88-95) is to make the rudder blade more balanced. This means moving the blade forward with respect to the axis of rotation on the pintles. This change does not affect the weather helm or the boats pull into the wind. What it does change is the force on the tiller that is needed to counter that weather helm. By moving the area of the blade forward the side force on the rudder is moved closer to the axis of rotation. This makes less torque on the rudder so the steering becomes easy and enjoyable. I made this modification to my rudder in '88, the first summer I had the boat.
The third modification is the addition of more area to the rudder. The original rudder, being undersize, causes a vicious cycle to develop. The cycle starts with the undersized rudder needing to be turned too far. This causes drag. The boat slows which then causes the rudder to stall. The stalling requires the rudder to be turned even further, which results in even more drag. This vicious cycle ends with complete loss of control, the boat head to wind and the skipper swearing at the boat. All that is needed is enough area to prevent this cycle from starting.
Modification of the rudder is the best improvement, by far, that I have made to my boat. The difference is amazing. There are two ways of changing the rudder. One is modifying what you have and the second is building a new one.
If you want to modify your rudder, you want to add to the front edge. You want to add about 2 1/2 inches. This will give you the benefits of increased area and a balanced rudder. The original rudder has its axis (of rotation on its pintles) about 1 1/2 inches AHEAD of the front of the rudder. Adding 2 1/2 inches gives a rudder that has its axis one inch BEHIND the front of the rudder. This makes a fantastic difference. One way to add this is to shape a piece of wood that you epoxy putty to the front edge of the rudder. Then glass over the wood and back onto the original rudder. Another way is to wax two pieces of masonite and clamp these (one on each side) to the rudder so the cavity can be filled with resin and cloth to extend the front edge. After this cures it is sanded to a fair curve on the front edge. Remember you want a very good aerodynamic shape.
The second way to improve your rudder is to build a new one. I built one last year as an experiment. I made it the same width (11 1/2") and increased the length 10 inches. I tested it on a day when there were strong puffs. I could heal the boat way over without loss of control. I had the chainplates in the water and their wake was splashing on the cabin windows. I not only could hold course I could head down if I wished. The tiller moved with only a little pressure and the boat responded instantly. This was more control than I wanted and decided to cut off 6 inches. The rudder is now 4 inches deeper than the original and has a square bottom. I find this rudder is much superior to the original. Since I moved the area 2 1/2 inches further forward the steering is very light. I shaped my rudder carefully to give it the proper shape for minimum drag and the most resistance to stall.
The photo with this article shows the original rudder next to the new one. The original has a notch (which I ground) in the front edge which allowed the rudder to swing down further. The original also has 1" added to the front. This moved the area forward resulting in a lighter helm but didn't make it more powerful. (It still rounded up) The new one is four inches deeper than the original and has the same shape all the way to the bottom.