Boat Lift Centering

I am making a wing for a pond boat. In a Standard sail there is a point called the center of
effort. An I correct in assuming the center of lift on a wing is at the maximum chord? Or
ia it elsewhere?

For standard airfoils, the center of lift is usually 1/3 back from the leading edge.

Chord is the distance from leading edge to trailing edge. Maximum chord usually occurs between the two halves of symmetric wings. The center of lift does lie on this line.

Chamber is the 'height' of the wing. Usually the highest point is 1/3 back from the leading edge.
For square wings thats the center of lift, for swept wings, some more calculations are needed that average the lift over the entire airfoil, (it will be a little further back)

2010-10-20 20:23:46 by j.hatheway@sbcglobal.net

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Remember the beginning of Scarface (1983), with the thousands of immigrants being departed from Cuba, you know with the synthesiser theme going on. You view all of these Cubans, taking rides on Cuban boats, US patrol and coastguard boats, unloading the Cuban cargo, while riots break out in Miami, after being let lose by Castro and eventually heading for Costa Rica, then finally Miami, which occurred in the summer of 1980. He also let out the "dredges" of Cuban society, his prisons and asylums, setting the occupants on the United States.

http://www.youtube.com/watch?v=Vkdia5RT2 Zw&feature=related


I guess you can compare it to women truly "entering" society for the first time, the workplace, and culture - which was previously male dominated. In ways it is very similar to an oppressed group of people, containing its own good and bad minorities. What you get is many honest, hard working women, but what you also get is, possibly unintentionally, the self-centred, narcissistic, gold digging, b!tchy, manly, manipulative, man-hating, gynocentric women - who were previously locked up, not in prisons but in traditional family homes.

Now men are coming to realise that feminism has set lose, more angry and self centred women than they thought there were in the first place.

It’s time for men to stand up for rights against these women who pose as feminists, but really could care less about the male sex and masculinity, and no wonder, end up taking away men’s rights and identity.

It’s the ignorant and gynocentric (not necessarily man-hating) “dredges” of feminism that should be challenged and exposed, not all feminists.

Do you agree with this analogy? If you do could elaborate on your opinions.

Scarface. It's amazing how that movie has resurfaced from almost obscurity over the past 5 years. Now it has quite the cult status. I hate the scene with the buzz saw and the shower. Makes me sick to my stomach to even think about it. (SHUDDER)

Every group has their extremists, which is what it looks like you are referring to here. Men SHOULD stand up for themselves, but no one can take your identity away. As for the roles of men I can understand; it does seem harder to be a man these days. But men and women seem to retaliate instead of try to make things better, which to me is where the problem truly lies.

Some women want to contribute more to society than cookies and kids.

2008-05-11 04:14:09 by Russell H

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stern sits low in water due to the fact you sit closer to the back of boat instead of being centered

You aren't really lifting the stern, you're depressing the bow. Add weight to the bow (water bags, sand bags, etc). It sounds a little like maybe you're a bit larger than your kayak designer was anticipating.

2008-08-12 19:03:00 by VW owner

Price: $475.00 $139.00

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I have a 1995 Kenner open fishing boat v bottom & center console with 90 hp Suzuki. At the dock where I am keeping the boat they want to keep it suspended out of the water at all times. The boat slip is set up with a hoist that is good up to about 7700 lbs. Thanks to my answer from Seattles I think my dry weight is about 1200 lbs plus 341 for the motor and plus fuel, 2 anchors, etc.
What I would like to know is the stress on the d-rings - 2 in the back and the one up front (not a lifting ring on the bow) I use this ring when I winch the boat out of the water on to the trailer.
At one of the marina's they used these same 3 rings for lifting my boat out in and out of the water from dry storage but never continuous weight hanging.
Will these rings hold this or should I have reinforcement plates and larger rings?
Thanks,
Josey

Those are used for tying the boat to the side of the pier,or winching it on to a trailer.They are not designed to hold the entire weight of the boat.It would be better to either trailer it or put slings under the hull with a chain hoist or hydraulic lift mechanism.

2010-04-05 12:03:02 by joseyboat

Ok, I've searched the net rather hard but no luck. Here's what I need. I want to build a heavy duty sailboat trailer that's open in the middle. You these in marinas as yard trailers where they can back up to a boat on stands, put cross beams under the boat on each side of the trailer and lift the boat off the stands and drive away. These things cost huge $$$, so I want to modify a heavy duty gooseneck trailer I already own. The problem is finding the axles. Standard trailer axles go all the way across. I want axles that just attach to each side of the trailer arms, thus leaving the center open. The axles are sometimes called walking beam. Other names - types are stub axles or even bogie axles. Weight capacity should be around standard 1 to 3 ton for each axle. I'll add more of them if they're lower capacity. Hydraulic actuation NOT needed.

I believe the axles you require are called "Torq-Flex" and can be sourced at Featherlite trailers.

Now, having said that, the trailer you're talking about is called a cradle-mover. They are designed to back under the sailboat cradle, put cross-beams under the cradle and transport it to where the Travelift can access the vessel and lift it into the water.

UNDER NO CIRCUMSTANCES should you support a sailboat on only two crossbeams! You require pads on the port and starboard sides (at least four, six is better) to prevent the vessel from tipping over during the lift/move. The keel takes the weight of the boat with the pads simply keeping the boat upright. The keel is the heaviest and most robust part of the hull.

Without a cradle, there is nothing to support the weight of the boat which is very stressful on the hull, not to mention the damage to the structural integrity of the vessel. Our trailer was designed and built to dry store our boat without a cradle or stands and can be seen at:

http://www.alohaowners.com/pages/project s/cradles/A27/27Cradle.htm

Ours is on the left side in the second row. "Ever After" is an Aloha 27-footer and weighs 5414 lbs, including 2200 lbs. of ballast. The trailer tongue can be extended 25 feet to launch her on the slipway. We always use the Travelift to take her out of the water in the fall as I've found it almost impossible to get her on the trailer perfectly straight at haul-out.

Hope this helps
Good Luck

2007-01-27 07:01:09 by carol