posted August 28, 2007 09:39 PM            

The rudder gantry was added. The rudder now had to be a little higher than before to keep the rudder head out of the water.

posted August 28, 2007 09:44 PM            

So . . .

Before

Then

And Now

posted August 28, 2007 09:51 PM            

This photo shows the modifications to the rudder head over the course of almost a decade.

We can ask D'Arcy for an opinion. That region much lower than the rudder pivot bolt may add very little to the support of the rudder blade. These unsupported extensions drag in the water and tend to cause the rudder head to split due to forces from the rudder blade. Sapphire's extensions were cut away in the first round of modifications.

When I thought my boat weighed only 1200 lbs, it made some sense to cut away some of the excess lumber. At 1700 lbs, it really does not matter.

Duchess II's rudder is the ultimate and may explain her speed compared to the rest of the fleet. That is a winter project to be considered.

posted August 29, 2007 09:45 AM               

If you look at the distance gained by being on the right tack you'll see that even a 1 degree shift gives you hundreds of feet over the boat on the wrong tack.

posted October 13, 2007 04:38 AM            

I was fishing for more info about these secret "radio communications" at the Bruce sail. But even after beers and brandy, the facts remained hidden.

So until the next time we meet, Orange Boat:

posted October 20, 2007 05:13 AM            

The tiller was a little too high at the grip end so the rudder head was returned to the shop. This is how it looked for the Thanksgiving weekend:

These photos were taken without the rudder blade installed (just in case you thought Sapphire had some ultra-low resistance, transparent rudder).

posted January 20, 2008 05:52 PM            

Remember This?

Here is one possible solution. A T-foil rudder to provide pitch damping and to also provide downward force as the boatspeed increases.

12 different templates have been painstakingly drawn. First a laminated plywood core will be hand-shaped. Then 0.097" of glass laminate will be applied and the whole thing will be templated again.

posted January 20, 2008 09:07 PM               

I think if you want to get Sapphire up planning Dennis, you're going to have to flatten the stern areas. Hanging the crew on triple trapezes and extension rails or wings to keep her flat will also help you power up your craft.

posted January 21, 2008 06:00 AM            

The intention is not to lift the Sandpiper onto plane. The intention is to force the stern down against the lift caused by the sailplan. The T-foil also has a reputation for reducing the up and down pitching of short hulls (like the I-14s). This damping effect makes the boat a little more efficient and maybe a little more comfortable. In the last America's Cup, one of the syndicates experimented with a T-foil as a way to make the boat's wake think that the boat's waterline was longer.

posted January 21, 2008 09:30 AM               

I think on smaller boats we should be shifting weight through crew positioning. Since wind and water conditions change quickley, a fast moving crew can respond better to almost any condition. It's the ability to quickley shift gears that makes our little boats so agile.

posted January 21, 2008 07:37 PM               

I'm going from memory here, but isn't 269 square inches quite a bit smaller than the standard rudder? Of course that high aspect ratio makes it efficient. If Duchess' rudder is any indication, you should not be lacking control.

posted January 27, 2008 05:31 AM            

I am anticipating a reduction in drag even though the T-foil will add another 100-150 sq.in. of area to the rudder shape.

Before Sapphire's rudder was cut to an elliptical plan form, it may have had 348 sq.in. of area.

The length from the pivot bolt to the tip of the existing rudder measures 34-3/4". That dimension for the new rudder will be 39-7/8". This will put the T-foil a very comfortable distance below the propeller of the outboard motor.

Here are a couple of photos. The laminated plywood has 2 layers of 6 oz glass and epoxy between. The 1-1/4" stainless steel angle will form the flange for the detachable T-foil. The core profile is bizarrely different than the rudder plan form.

posted January 29, 2008 11:48 PM               

You can probably design a long broom handled device with carpeted claw to swipe weeds off. It's almost a standard item when racing in shallow areas where weeds grow in August. Clean it often. One little weed will really slow you down.

On Sharks which are similar to Sandpipers in that they have very inefficient keels, we tend to keep the ruddrs big. Besides steering, they also give some lateral resistance. Keep in mind that the newer designed boats have highly efficient keels so your rudder only has to steer.

Sandpipers have a lot of grey areas when it comes to desgn. That's what makes them so neat. For example, when a larger America's Cup styled boat runs downwind the long waterline makes it behave just like a test hull in a tank. Our short little hulls are bobbing all over the place causing a lot of turbulance behind the keel. On the plus side though you can move your weight to help the hull. As the hull climbs over a wave we often shift our weight forward. At the same time we pump the sails. The two actions cause the boat to jump onto the wave and surf a bit. As the speed picks up we move back to stay on the wave.

I'm not sure if the lower wing on the rudder will help you in a boat where conditions often require weight shifting and balance to control the boat.

Back in the 70s while racing Lasers we were fortunate to have Ian Bruce (Designer of the Laser) sailing with us for a day. When we asked him about the best way to get a really smooth rudder he suggested doing nothing. Again, he felt there was so much turbulance behind the centreboard on a small boat that your time would be better spent sailing, learning to play wind shifts and waves.