What are fore and aft balance symptoms?

[Rick Macdonald]

I just looked in the archive and found a thread about fore and aft balance. Nobody actually explained how you can tell and what the problems and issues are. And how much does it matter to move 100 pounds of batteries foreward about 8 feet when from one day to the next your crew weight can vary a few hundred pounds?

 

[Tom Wootton]

If I understand correctly,...

...balance is the relationship between the center of effort (CE) of the sailplan and the center of lateral resistance (CLR) of the underwater portion of the hull. You can affect CLR by shifting weight fore and aft, and by adjusting the angle of the centerboard if you have one. On my boat, the rudder swings up if it hits bottom, and it's amazing how a slight change in rudder angle affects balance. Heel angle also alters CLR. You can affect CE by adjusting mast rake, and by reefing the main and/or jib. All this manifests as weather or lee helm. The ideal is a slight weather helm (tendency to head up into the wind when you release the wheel/tiller). This happens when the CE is slightly aft of the CLR. So, shifting weight forward presumably would help correct lee helm by submerging the forward part of the hull more, moving CLR forward.

 

[Rick Macdonald]

Makes sense

I see, thanks! I can test this next time I'm out by triming the sails such that it goes straight when the tiller is let go. Then I'll have my 300 lb sailing buddy go forward and stand on the anchor well. I should see a weather helm appear.Still, sometimes I'm out with one person for a total crew weight of 300 pounds and sometimes I have a full cockpit of up to 1000 pounds. Unless one sails most of the time with the same crew weight, I'm surprised that people are able to pick some fore/aft balance target and adjust to it.Maybe the point that I'm missing is the case where with almost any amount of crew in the cockpit there is a cronic lee helm and that's why and when they put ballast forward. Is that the scenario when the issue arises?

 

[Brigg Franklin]

Moveable ballast

Crew is moveable ballast and can be asked to move forward or hang out over the edge. If the boat starts out with some weather helm, which is good, you can pack supplies in the bow or move them around to balance for more people in the cockpit. Just remember, with weather helm your boat will head up in the puffs, which is good, and with lee helm it will head down in puffs which is dangerious and can cause a broach.

 

[Jim Honeyman]

lead in bow

I have placed 150 lb of lead under my v-berth to of set the weight of my crew and out board. With is weight I can sail with the main only in winds over 15 miles per hour and have good control on the tiller. With out the lead the chop pushes the bow to leeward and I have to constantly corect the sterage. I sail a H22 on an inland lake.