Post by Cybermortis on Sept 18, 2014 10:09:34 GMT
The reason for putting a sail as high up as is practical/possible is that the wind is more consistent and usually stronger.
If you look at the sail plans of old sailing frigates they seem to have used topsails far more often than the main sails (and the spanker very rarely), especially when they wanted to go fast. (In combat ships sailed under topsails, but I suspect this was because the mainsails blocked line of sight from the quarterdeck. And as such they were used only when/if the topsails and yards were damaged.
The sail needs to be a little more than 'just above' the superstructure, since turbulence could affect a sail some distance above the physical height of the structure - You can actually see this in some of the turbulence testing MB have done over the years with cars in the wind/water tunnels, where the turbulence raises a significant distance above the body of the car. That said with a parachute you can deploy it further away from the structure, certainly a lot further away than you could with a traditional sail on a mast as the line to the 'chute can be extended so it is catching the wind from over the bow or sides of the ship.
In regards sending a sign up, that is a minor consideration at best. Parachutes are fabric, so don't show up on radar, and by the time anyone is close enough to spot the 'chutes they would notice the rest of the ship anyway. The primary consideration in a warzone is getting as far away from the place you were attacked as possible as fast as possible. Whoever just attacked you has probably radioed your position in, and you have to assume that a second strike is being directed at your position. In such a situation even a couple of miles distance can mean the difference between avoiding that second strike and being sunk.
Parachutes actually have one advantage over a mast and sail in some regards, specifically that they are totally silent. Masts will, as I noted, be constantly shifting position which will make noise that will be transmitted to the hull and through the hull into the water. This makes it easier to use passive sonar to detect a ship with a mast and sail as it is making more noise.
They did not, from what I can tell, use a rocket launcher. I think they used the grenade attachments that are fitted to the end of a rifle, or a grappling gun (which are used to pass a line from one ship to another during resupply when at sea). I suspect that the system uses the 'grapple' to fire a smaller drogue into the air, and that this then catches the wind and pulls the main 'chute up to deploy. This would allow deployment by one man using equipment that is already standard on the ship - meaning that the only part of this emergency propulsion system that the ship needs to carry that it otherwise has no use for is the parachutes themselves. Those they can fit into a locker or two without having to take up space that is needed for more important (or more frequently used) items.
If you look at the sail plans of old sailing frigates they seem to have used topsails far more often than the main sails (and the spanker very rarely), especially when they wanted to go fast. (In combat ships sailed under topsails, but I suspect this was because the mainsails blocked line of sight from the quarterdeck. And as such they were used only when/if the topsails and yards were damaged.
The sail needs to be a little more than 'just above' the superstructure, since turbulence could affect a sail some distance above the physical height of the structure - You can actually see this in some of the turbulence testing MB have done over the years with cars in the wind/water tunnels, where the turbulence raises a significant distance above the body of the car. That said with a parachute you can deploy it further away from the structure, certainly a lot further away than you could with a traditional sail on a mast as the line to the 'chute can be extended so it is catching the wind from over the bow or sides of the ship.
In regards sending a sign up, that is a minor consideration at best. Parachutes are fabric, so don't show up on radar, and by the time anyone is close enough to spot the 'chutes they would notice the rest of the ship anyway. The primary consideration in a warzone is getting as far away from the place you were attacked as possible as fast as possible. Whoever just attacked you has probably radioed your position in, and you have to assume that a second strike is being directed at your position. In such a situation even a couple of miles distance can mean the difference between avoiding that second strike and being sunk.
Parachutes actually have one advantage over a mast and sail in some regards, specifically that they are totally silent. Masts will, as I noted, be constantly shifting position which will make noise that will be transmitted to the hull and through the hull into the water. This makes it easier to use passive sonar to detect a ship with a mast and sail as it is making more noise.
They did not, from what I can tell, use a rocket launcher. I think they used the grenade attachments that are fitted to the end of a rifle, or a grappling gun (which are used to pass a line from one ship to another during resupply when at sea). I suspect that the system uses the 'grapple' to fire a smaller drogue into the air, and that this then catches the wind and pulls the main 'chute up to deploy. This would allow deployment by one man using equipment that is already standard on the ship - meaning that the only part of this emergency propulsion system that the ship needs to carry that it otherwise has no use for is the parachutes themselves. Those they can fit into a locker or two without having to take up space that is needed for more important (or more frequently used) items.