what you are talking about above are wing tip vorticies.they are i believe designed to reduce the turbulent airflow at the wingtip but from the boeing site winglets arefor the 737 line:
Benefits
Depending on the airplane, its cargo, the airline's routes and other factors, winglets have the potential to give:
IMPROVED TAKEOFF PERFORMANCE

By allowing a steeper climb, winglets pay off in better takeoff performance, especially from obstacle-limited, high, hot, weight-limited, and/or noise-restricted airports. Performance Improved climb gradients increase 737-800 allowable takeoff weight (TOW).

Some examples include:

Chicago-Midway: ~1,600 lb additional TOW
Lanzarote (Canary Islands): ~3,500 lb additional TOW
Albuquerque, Denver, and Salt Lake City: ~4,400 lb additional TOW
REDUCED ENGINE MAINTENANCE COSTS

Better climb performance also allows lower thrust settings, thus extending engine life and reducing maintenance costs. Lower Required Thrust Levels Extend On-Wing Life.

Takeoff - Winglets allow up to 3% incremental derate.

Cruise - Cruise thrust levels are reduced by up to 4%.

FUEL SAVINGS

Winglets lower drag and improve aerodynamic efficiency, thus reducing fuel burn. Depending on the missions you fly, blended winglets can improve cruise fuel mileage up to 6 percent, especially important during a time of rising fuel prices.

INCREASED PAYLOAD RANGE

The addition of Aviation Partners Blended Winglets to the 737 Next Generation has demonstrated drag reduction in the 5 to 7% range that measurably increases range and fuel efficiency . In addition, the Blended Winglets allow the 737-NG to take off from higher, hotter airports with increased payload.

Series Range (nm) Normal Range (nm) With Winglets
-700 3250 3634
-800 2930 3060
-900 2670 2725



ENVIRONMENTALLY FRIENDLY

With winglets, you can be a good neighbour in the community you serve. They enhance performance at noise-restricted airports and cut the affected area by 6.5 percent, saving you money on airport noise quotas or fines. By reducing fuel consumption, winglets help lower NOx emissions by 5%.

IMPROVED OPERATIONAL FLEXIBILITY

By increasing Payload Range and Overall Performance, Blended Winglets add flexibility to fleet operations and route selection. Air Berlin notes, "Previously, we'd step-climb from 35,000 to 41,000 feet. With Blended Winglets, we can now climb direct to 41,000 feet where traffic congestion is much less and we can take advantage of direct routings and shortcuts which we could not otherwise consider."

MODERN DRAMATIC APPEARANCE

Blended Winglets bring a modern look and feel to aircraft, and improve customers' perceptions of the reliability and modernity of the Airline.



Dimensions
Each winglet is 8 feet long and 4 feet in width at the base, narrowing to approximately two feet at the tip.

Added wingspan
Winglets add approximately 5 feet to the airplane's total wingspan - from 112 feet 7 inches to 117 feet 2 inches. (All Next-Generation 737 models have the same wingspan