I checked with Dr. Yates, and he sent this for you:
Askew can be traced to a Norman William de Ascough, named after Aiscough, an Old Norse place-name. His family could have been Jewish or crypto-Jewish, particularly since he was “father of the English navy.” Other admirals and naval administrators who were crypto-Jewish were William Penn, John Pepys and Sir Charles Howard, 1st Earl of Nottingham. Many of these are discussed in "Jews and Muslims in British Colonial America," esp. chapter one, "Mapmakers, Privateers and Promoters." But the name itself is Old Norse/Norman and seems to have something to do with an oak.http://www.surnamedb.com/Surname/Askew
Donald N. Yates, Ph.D.
P.O. Box 2477
Longmont, CO 80502
tel. 480 email@example.com
Hope this helps,