Both are Gargantuan creatures, so the numbers should work.
We should also give it a special attack that emulates its ability to constrict ships to deal the equivalent of ramming damage. Here's how the ramming attack usually looks:
Ramming (Ex): As a standard action during its turn each round, an ocean strider can swim at up to quadruple speed (240 feet) and ram a waterborne target (such as a ship or another creature). To ram, the ocean strider must end its movement in the target's space. This attack deals 2d8+6 points of damage. If the target is a creature, it can attempt either an attack of opportunity or a DC 29 Reflex save for half damage. The save DC is Strength-based.
Upon ramming a ship, the ocean strider can make a Strength check to breach its hull, which causes the ship to sink in 1d10 minutes. The break DC varies with the type of vessel rammed, as follows: rowboat DC 20, keelboat DC 23, sailing ship or longship DC 25, warship DC 27, or galley DC 30. (See Chapter 5 of the DMG for information about ships). Regardless of the check result, every creature aboard must attempt a Reflex saving throw (DC 15). Success means the creature takes 1d10 points of damage from being thrown about by the impact; failure means the creature is hurled overboard.