If you will look at the ancient example above you can see the holes where the bolts attached it to the hull. Of course, the structure had to be designed to absorb the impact. There were instances where the ram became ensnared & the victim sank the attacker.How was the actual ram or prow attached to the boat? It surely wasn't bolted onto the hull.
Granted the prow of a ram is under the waterline but can you tell a ram from another sort of ship just by looking at it?Are there other features that designates a ship as a ram?
As I alluded to above, the target vessels for these were usually thin racing shells rather than the ribbed construction of Atlantic (and later Mediterranean) vessels. This is because rowed warships need to be rowed, usually at speed for short bursts in battle (as much as nine knots) and at lower speeds of ca. 4 knots for long periods of time during the manoeuvering around a battle. Under those circumstances you want as little weight as possible.That's a unique design. It looks like it was designed to separate the planks.