A warship weapon which found favour in the great naval battles of the 19^th century, the ram bow morphed into the modern-day bulbous bow to become a cornerstone of modern ship design.

In ancient times, the most important weapon a naval vessel possessed was its ram bow.

Galleys would be propelled at maximum speed by slave oarsmen with the intention of smashing into an enemy ship, often with dire consequences. But, the arrival of gunpowder and the cannon which could hit another vessel, and possibly sink it, at a distance, meant such tactics and the ram itself fell into disuse. That is until the battle of Lissa.

Ram reborn

Rams were used during the American Civil War as a temporary measure with limited success. However, it was only in 1866 during the Third Italian War of Independence between Austria and Italy that major navies realised the true potential of this weapon for ocean-going warships.

The ram bow as part of the design of a major warship had already been adopted by many navies when it was thought that ever-stronger armour negated the effects of gunfire, and that ramming might be a viable alternative. It was the major naval engagement that took place on 20 July in the Adriatic Sea near the island of Lissa that proved this theory. This was the first encounter between ironclads, and it saw the Austrian flagship Erzherzog Ferdinand Max ram and sink the Italian Re d’Italia.

Rams for all

Following Lissa, navies everywhere made the ram bow a key feature of their ships and their operational tactics. However, the passing of time and gradual improvements in gunnery ranges and power meant the use of ramming became less popular in battle, although it was not phased out of designs until the 1920s.

The French ironclad Redoutable of 1878 demonstrates the combination of a ram bow with a bowsprit that was typical of vessels of that era

Dangerous downside

The effectiveness of the ram to sink its own sisterships was demonstrated all too often. From 1870 onwards there were many collisions involving a ram bow, in some cases resulting in the damaged vessel sinking.

Two British cases were those of HMS Iron Duke ramming and sinking HMS Vanguard in 1875, and the infamous collision in 1893 between HMS Camperdown and HMS Victoria, with the latter sinking. In 1878, the German ships Grosser Kurfurst and Kong Wilhelm also collided, with the former sinking.

Ramming submarines

The one situation where ramming turned out to be particularly effective against an enemy was the sinking of submarines. During the First World War, 19 German U-boats were sunk by ramming including one, the U29, by the battleship HMS Dreadnought with its ram bow. Admittedly, most sinkings were by vessels with conventional bows rolling over the surfaced submarine.

A similar situation happened during the Second World War, with 27 U-boats being rammed (according to statistics up to May 1943), of which 24 sank, proving that ramming could be effective in very specific situations even without a special bow. However, damage to the ship which did the ramming was often substantial and it was increasingly frowned upon.

The bulbous bow emerges

But there was one rather surprising discovery about the ram bow.

Warship towing tests to determine their hull resistance became increasingly common in the 19th century, and it was noted that those with ram bows had reduced resistance.

It led David W Taylor, a naval architect who served as Chief Constructor of the United States Navy during the First World War, to develop the concept of the bulbous bow. He incorporated this variation of the ram bow in his design for the US battleship Delaware of 1910.

What had been discovered was that the ram, protruding below the waterline and forward of that part of the bow at the waterline, created an underwater wave that, if positioned correctly, counteracted the wave created at the waterline. Although the bulb wave required energy, cancelling out the bow wave stream, it changed the pressure distribution along the hull, reducing wave resistance. More energy would be available for greater speed or less would be needed to maintain a certain speed. And helpfully it could save fuel costs too.

There was little interest in the concept until the 1920s when its value began to be appreciated and it was applied to a number of passenger liners including the Bremen, Europa, President Coolidge and Normandie. By the 1950s onwards, thanks to research by Dr Takao Inui of Japan, the value of the bulbous bow was confirmed and became standard on the vast majority of ships.

The modern cruise ship Symphony of the Seas has a bulbous bow fitted with four bow thrusters for added manoeuvrability

Design limitations

However, it does have limitations. It is only really effective at one draught so, if set for a fully-laden vessel, it will not be as effective in ballast.

Then there’s the fact that it may cause increased slamming. It’s why some modern ships have abandoned the concept for other bow designs.

John Barnes is a writer and author, specialising in maritime.