Slingshot sits at 20/1 in the Afloat stakes.
Dowling had to fasten a new main to the boat after theirs was shredded in a RORC offshore earlier in the season.
Between himself and his sailing partner, Michael Boyd, the pair have already won a Round Ireland, and came close again in 2006, when weather snatched what was looking like an overall victory from them and the rest of their crew. This year they're heading up an 11-strong doublehanded entry.