Comparison of Modern Keel Types for Sailing Yachts
Artikel i vetenskaplig tidskrift, 2018

The performance of three bulb keels is compared with that of a traditional fin keel. Hydrodynamic data from wind tunnel tests are used in a velocity prediction program (VPP) with the keels fitted to a 40’ cruising yacht. Two scenarios are investigated: keel retrofitting and new design. In retrofitting, the sail, mast and rig are unchanged, while in new design they are varied to obtain a constant heel angle (Dellenbaugh). Three keel materials are considered: cast iron, lead or a mix thereof. As expected, the bulb keels are superior to the fin keel in all but the lightest winds in the retrofit scenario. The differences between the bulb keels are small, but the keel with a bulb integrated with the fin is slightly slower than the keels with more distinct bulbs, in either L- or T-configuration. These are very close in retrofit, but the T-configuration has a slight advantage in the new design scenario.


Kasper Ljungqvist

SSPA Sweden AB

Michal Orych

Flowtech International AB

Lars Larsson

Chalmers, Mekanik och maritima vetenskaper, Marin teknik

Christian Finnsgård

SSPA Sweden AB

Transactions of the Royal Institution of Naval Architects Part B: InternationalJournal of Small Craft Technology

1740-0694 (ISSN)

Vol. 159 81-88 203