LOFT 11 Demo Version


Demonstration version of LOFT 11 Keel and Rudder Design. Does not save designs or export printing or CAD Files.

SKU: LOFTDemo Category:


LOFT is now LOFT 11! It has been rewritten for WINDOWS 10 & 11. We have added new features, added new plotting and printing capability and updated all of the File Open / Save etc dialogs to allow all of the new long name conventions of the newer versions of Windows. LOFT 11 is also super fast – and easy to use. Give it a try for your keel or rudder design projects, even hobbyists will enjoy this powerful low cost program. LOFT 11 now runs at very high 4K resolution on high speed graphics cards and new high resolution monitors.
LOFT makes the design of typical keels and rudders a quick and pleasant task. A planform is designed by simply entering the desired keel or rudder span, leading edge sweep angle, then root and tip chord lengths and thicknesses.
New FOIL Capabilities!
Click on one of 5 NACA or NASA foil types from the list included with LOFT or NEW – Choose any WINGS 10 Foil shape or any symmetric foil shape designed in FOIL 10!. The chosen foil shape will be scaled in thickness to the desired amount at the root and tip and linearly tapered between the root and tip thickness values.
Multiple Trailing Edge Shapes
LOFT allows your choice of elliptical or parabolic trailing edge shapes that can be adjusted in curvature from virtually straight lines to tortured curves.
Ballast Definition for Keels or Weight Estimate for Rudders

If this is a keel design, you can choose a ballast density, top of ballast depth and the angle of the top of ballast. Now click on the CALC menu and LOFT 11 computes 11 ballast and performance values including : Vertical and lateral center of gravity, frontal area, wetted area, aspect ratio, weight, and average chord length. Modify any design parameter while tracking the potential performance factors of aspect ratio, wetted area and frontal area.

If a rudder is being designed, and the density of the core material is known, it can be entered as a “ballast”. Now the weight of the completed rudder can be estimated without the stock. A lightweight rudder is important to performance in MORC, IMS, IOR or PHRF racing sailboats to minimize pitching moment.
LOFT 11 provides an estimate of the center of effort in span and chordwise location and gives an indication of the distribution of lift force (side force on a keel or rudder) relative to the ideal loading to achieve minimum induced (vortex) drag. Change the leading edge sweep angle and taper from root to tip until the actual load line approaches the optimum load line. When the distance between the two curves in minimized, you can be assured of top performance from your keel or rudder.

LOFT 11 now includes the Lift and Drag Force computations of our old program KLIFDRA. Now accurate predictions of the amount of Lift (Side force) and Drag are computed in addition to LIFT to Drag Ratio – a measure of the design efficiency.

A new feature of LOFT 11 is a Ballast Trade Study plot. This new feature shows you the amount of ballast and the location of the center of gravity as a function of the position of the top of the ballast within the keel. Now that the keel or rudder is designed, it remains to have it built.


LOFT 11 provides extensive CAD output file support in the form of 2D DXF files. Offsets can be exported to virtually any CAD program that reads the universal DXF format. Now you can make full size patterns for submittal to the keel foundry.

Record the calculations of keel or rudder characteristics and a picture of the project by printing screen copies directly to ink jet or laser printers. In addition to all of these essential features LOFT adds these features:

  • Uses foil shapes designed by FOIL 10 for WINGS 10
  • CAD output provides overlaid foils in plan view to aid in keel bolt location
  • Provided with 5 Standard NACA and NASA foil shapes
  • High Quality Screen Prints of LOFT Designs
  • Prints offsets and keel or rudder characteristics
  • LIFT and DRAG Analysis


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