I would also presume that the addition of this mechanic would make the presumably unintended, but opposite true as well. If a small ship can grapple a large at speed, physically the opposite should be true as well. If the reasoning being is that a lighter ship is easier to pull against a larger ship, it goes both ways. A large ship would be able to board a small ship at speed for the same reason, and I think this would defeat the purpose of this (small ship balancing) mechanic you propose.
It might physically make more sense, but it doesn't enhance the game play for either side. It just makes both ships more vulnerable to trolling depending on who decides to utilize it to their advantage.