You can trawl the bait at various speeds, 4-9kmh. As the whole bait is well secured onto the plastic tube and hook, it gives the bait more stability while trawling at a faster speed, so you can cover more ground.
If you are not getting a hook up when trawling passed a shoal of Natal Snoek, best you pick up the rod and point the tip to sky. When you see the fillet come to the surface, then drop your rod down to where it was. This will make the Natal Snoek think their prey is escaping and should turn them into a feeding frenzy.
My best times to target Natal Snoek are Spring Tide and Leap Tide. Also early morning and late afternoon.
Hope this will help you as it helps me!!!