NAVAL EXPERIMENT.

Evening Post, Volume LXXVII, Issue 63, 11 September 1909, Page 3

NAVAL EXPERIMENT.

JUMPING A BOOM.

(From Our Own Correspondent.)

LONDON, 3Qth July. The experiment of jumping a harbour defence boom was made by the torpedoboat destroyer Ferret at Portsmouth on Wednesday, and the result of the test proved that the obstruction which is stretched across the narrow harbour entrance as a protection against torpedo craft is not the invulnerable defence which it has been always believed to be. /

For the purposes of tho trial a section of the boom was taken from the Blockhouse side of the harbour, where it is stored in readiness for immediate use, and placed at a shallow spot in the Fareham Creek, near the Fisgard training ship for boy artificers. Here it was firmly secured between two large dockyard lighters, a red flag placed in the centre, indicating the spot where the 'destroyer was to strike. The boom consists of baulks of creosoted timber about 12ft long, 18in wide, and 12in thick. To the outward edges of each length is firmly attached a steel spike, with a sfecond line of spikes, also pointing outwards, half-way along. The timbers are then secured side by side at intervals of about half a yard by massive •steel hawsers, offering' what has been hitherto believed to be an unsurmountable obstruction to smaller naval craft. The Ferret was specially strengthened for- the daring enterprise. To her frail stempiece had been riveted plates of hardened steel, with a bladelike erection extending over the deck to the forecastle Thib was apparently with 'the object of severing the 3in steel hawser which is raised above the boom in order to clear the decks of any small craft which may venture to charge it. The .broken steering gear which prevented the test taking place on Tuesday hav-' ing been repaired, the Ferret, with ncr volunteer orew, left harbour before daybreak, and after running a short trial at Spithead, started on her perilous mission.

A few minutes after 5 o'clock'tho little black craft dashed into the harbour, and threading her way between the cruisers lying at moorings, charged the boom at about fifteen to twenty knots. The effect was remarkable. The great wires snapped like string, and the timbers parted as the way of the vessel drove her through them. The Ferret passed on clear of the floating works, and then with her own engines put astern she came to a stop. At first it seemed that she was undamaged, but afterwards seen with powerful glasses some dents in her side showed where the iron-pro-tected timbers had struck. A tug then steamed alongside and took her to tho dockyard. The vessel did not leak, and when she was subsequently placed in the deep dock for examination the dam> age she had sustained was found to be only of the most superficial character.