The position of the torpedo is known, and the tow line is never in contact with the enemy during the operation; a skilled hand at the brakes is all that is required, the vessel keeping a straight course at the highest speed, passing as close as possible to the enemy, in order to clear away all obstructions. The tow rope must not be checked by the brake too suddenly. _Defensive Purposes._--The Harvey torpedo may be used as a means of defence by large ships against a torpedo vessel attacking with that species of submarine weapon, as the latter would be forced to pass outside the former vessel's torpedo, and thus decrease the chance of a successful dip. Again, in the case of an attack by the ram, these torpedoes afford some protection, as a deterrent. _Night time._--Though a dark night and tempestuous are favourable to a surprise, yet in the case of a Harvey torpedo attack it is essential that the weapon should be seen to dip it at the proper time, therefore daylight is necessary to this species of torpedo attack. _Value of the Harvey Torpedo._--The Harvey torpedo is undoubtedly of considerable value when _ably handled_, yet the skill and judgment required is very great, and can only be acquired by _constant_ practice. _Description of the Menzing Towing Torpedo._--This modified form of the Harvey towing torpedo was designed by Captain Menzing, of the German navy, to remedy what is considered by the Germans as the chief defect of that weapon, viz. its liability to injure friendly vessels, and also to do away with the necessity of using two torpedoes, one for each side of a ship. At Fig. 117 is shown a plan and elevation of this towing torpedo. _a_ is the body of the torpedo, somewhat similar to the Harvey, but narrower at the stern, and bevelled on both sides towards the bow; _b_ is an iron frame placed in the bow, capable of being turned either to the right or left; _c_ is the hole for the introduction of the fuze, and _d_ is the loading hole; _e_ is a rudder placed at the stern of the torpedo; _f_, _f_ are levers, by pressure against which the torpedo may be fired mechanically, or electrically at will; these levers are connected to a block of wood fitted with stops to prevent them being pushed too far over; _s_ and _p_ are two towing ropes, one on each side of the torpedo, which pass from its stern through the point of the frame _b_, and thence to the vessel, these are also connected to the rudder _e_ in such a manner that on either of the ropes _s_ and _p_ being tautened the rudder _e_ is turned in the opposite direction; _w_ is an electric cable, strong enough to bear the whole pressure of the torpedo when being towed right aft.