  The Collatz and $abc$ conjectures, both well known and thoroughly studied,
appear to be largely unrelated at first sight. We show that assuming the $abc$
conjecture true is helpful to improve the lower bound of integers initiating a
particular type of Collatz sequences, namely finite sequences of a given length
where all terms but one are odd with the usual ``shortcut'' form. To obtain
sharper bounds in this context, we are led to consider a small subset of the
$abc$-hits. Then, it turns out that Collatz iterations as well as Wieferich
primes may be used to find large triples in this subset.
