That being true then what benefits does a vertical rudder bring? So far this thread
has said "easier in heavy air" without explanation. If "easier" means less pressure on
the tiller handle, I myself find hardly any counter-force on the tiller in heavy winds.
The only other thing I can think of is the added surface area would keep the boat tracking
straighter. The brings us back full circle to using the Laser rudder design. I'm outta here,
pulling the ejection handle, popping the canopy, hitting the silk, heading to sunnier threads.
The vertical rudder moves the center of effort closer to the transom, reducing the lever arm that the swept back rudder has so you wouldn't have to move the gooseneck back so far. As to whether that is an advantage of any type I don't know. The rudder certainly doesn't need any more sudden surface area. I have never heard of a Sunfish "not tracking." If the boat is properly trimmed with little helm you shouldn't need the rudder to keep it going straight. That usually comes close to reality but you usually need some rudder, but you don't want any more drag than necessary so the current sized rudder is just fine.
Some of you are wondering why I won't just move the gooseneck position so the boat will sail with a neutral helm even when the wind blows. Here's your answer.
Below is a screen shot of my brother sailing the Sunfish close hauled. In that screen shot, the gooseneck is at the 18 inch mark, back from the forward end of the boom. Yes... I have an adjustable gooseneck and yes... I have my boom marked in one inch increments. From 16 to 22 inches.
When I was sailing the boat recently on one of my out and returns, I encountered the usual 20-ish mph winds in a venturi area that I sail through during the trip. Around the corner in the river before the venturi where there is less wind, I luffed up, crawled forward and moved the gooseneck to 22 inches. I then sailed through the venturi with the 20-ish mph winds. Moving the gooseneck to this position had a negligible effect on the weather helm. Even when sailing the boat flat.
Why? Because moving the gooseneck position alone doesn't move the center of effort forward enough on my boat. If I wanted to have the boat in trim, I'd move the attachment point of the halyard higher up on the upper boom, which would allow me to have where the two booms join up forward right off the deck and sail with a very low boom that one has to duck quite a bit to get under. Like my Laser with a lot of vang.
But that's not the way I want to have the boat set up. My brother likes not having to tuck way down when tacking or jibing... nor does my hang gliding buddy who also likes to sail the Sunfish. When the winds are light, the helm is balanced with the boat in this configuration. But when it gets to 15-ish, the weather helm increases in a big way. Having a rudder that is vertical... or nearly vertical... eliminates this issue. That's why I'm installing a vertical rudder.
In case you are wondering, that all white sail in the photo is a race sail. An old, dirty one (yes... the previous owner again ) but one with low hours on it. So, it's not a bagged out, soft cloth, OEM bed sheet. It has good manners and not even so much as a quiver in the leech at all wind speeds. So, my rapidly building weather helm isn't the result of a poor quality sail. And I don't have the sail set in full mode. I've got it set at what you might call, "medium/tight". Ie, no vertical wrinkles at the foot and no horizontal wrinkles at the luff.
So, that's why I'm going with a vertical rudder. It did wonders when I made one before (as I recall, I just flipped the existing rudder front to back and sailed with the vertical, trailing edge facing forward) and will likely do so again.
Do you have a Cunningham, adjustable outhaul and hiking strap? The racing sails have a lot of draft so sail controls are important. The cunningham would allow you to move the center of effort. The top of the sail is very tight to the end of the boom. You want scallops down the front of the sail for power. Sunfish - Starboard Passage. Hiking strap allows you to get more weight out in heavy air which eliminates weather helm.
The racing sails have a lot of draft so sail controls are important. The cunningham would allow you to move the center of effort. The top of the sail is very tight to the end of the boom. You want scallops down the front of the sail for power.
My brother and my hang gliding buddy don't want to have to hike way out to the degree that a hiking strap allows you to. Nor do they have the physical capability to do so for an extended period of time if the wind really comes up. A vertical rudder allows for a much more neutral helm in stronger winds even when the boat is not sailed flat.
Plus, as I said in my previous post, when I had the gooseneck set at 22 inches and sailed up through the venturi in the 20 mph winds, "moving the gooseneck to this position had a negligible effect on the weather helm. Even when sailing the boat flat".
I'm also pondering whether the previous owner may have made another rudder that was mounted with the blade slightly more raised than stock. Just a few degrees makes a difference. When sailing my 470 powered up with a bud on the trapeze in big winds years ago, I could start to feel weather helm increasing just from the rope that holds the rudder in the vertical position starting to stretch.