In the future, submarines won't have sails
 

True or False. In the future, submarines won't have sails at all. Discuss.

My opinion? I don't see why they havn't gotten rid of them a long time ago... quote from the 'Submarine of the Future Task Force' out of the 'Office of the Secetary of Defense for Acquisition and Technology'... http://www.fas.org/man/dod-101/sys/ship/docs/sotf.htm

Subs will sure look funny without those sails. :yep:

Refine your question: How far into the future? The next class of boats, or the boat of the next century? In whose navy will this appear?

One reason that the sail hasn't gone away yet is that it provides protection for sensors and devices that must be extended above the surface of the water; it also assists with stealth for the same reason. Imagine having to come almost completely to the surface to poke your scope or radio antenna out of the water!! One bad wave at high sea state and "Hello World! Here I am!" Having a sail in place provides a way to keep the hull beneath the surface while your masts and antennas are extended.

I don't dispute that in the future, there may be ways to eliminate the sail for this purpose by creating a bouyant sensor pod that contains scopes and comm and detection antennas, even though this does not address the need for stealth and protection while using a snorkel mast, which is still used in normal and emergency ventilation situations.

TG

That's just an excuse for poorly trained diving officers!!
Captain: "Ensign! Make your depth 12ft exactly and hold that position exactly and compensate for the wave effects 100% with pinpoint psychic percision!"
Ensign: "Errr............."

I left the timeframe open in the hopes of provocating a little discussion. :)

How would you operate the submarine in shallow waters with bad weather, when there isnt enough water to dive out of the way you need the sail to A stop water flooding down into the submarine B to house the masts and other vital equipment.

Russian subs have bad weather bridges i cant see them going any time soon.

You're assuming that the different masts actually have to retract inside the hull.
What about new types of masts that fold onto themselves without penetrating the submarines hull ?
An example is the us navy new asds (advanced seal delivery system) submarine whose periscope mast and eletronics mast do not retract into the hull.

During the late 1960 the american navy considered a new type of nuclear propelled submarine that didn't have a traditional sail, and in which the mast would fold down onto the hull instead of penetrating it.
The project was codemaned CONFORM.
Unfortunately the concepts were just too advanced for the time and Admiral Rickover just pushed the study aside.

(You can find more information about the CONFORM project in Polmar's book Cold War Submarines).

The quote from the start of the thread is from the literature associated with the next generation SSN project (meaning the generation AFTER Virginia). Every picture I have seen of that hypothetical next generation boat (which is already in the beginning design phases for building 15-20 years down the road) has a sail. Most of the focus there is replacing the torpedo room/VLS tubes/Stratweps tubes with modular free-flood areas that are much more flexible. I think the pain we went through in converting the SSGNs inspired a little bit of that, and I would really like to see how far they take that idea of open modularity. The guys at NUWC are always thinking several years ahead, and their ideas at times are just awesome. They are the ones who gave us ADCAP after all, as well as UUVs, ASDS, predator drones launched from submarines, and assorted other coolness.

An interesting note: The US is finally starting to get away from those stupid straight up-and-down submarine sails. Look for the new Virginias to look like Akulas without the big TA fairing on the rudder.

For the last time that image is not real! :damn:

I read something about
"Russian subs still use low-profile sails, indicating intelligence gathering isn't a priority ... sails provide stabilization for when using ..."
Or something to that effect. I don't know if the source knew what he was talking about.

I don't understand the "bomb bay" torpedo concept... is there a diagram somewhere or something? I'd like to get a better idea of it. I don't see how you could launch a torpedo that's not in a tube... :huh:

Umm... letting it fall out of a hatch before turning on the power to the engine? Like airplanes do with internally carried missiles?

What image? I caught it off a NUWC brief about weapons.

I'm not very good with physics, especially water based physics (but I know enough to operate subsims) but wouldn't the total removal of the sail make the submarine unstable?

Re: In the future, submarines won't have sails
 

Sails cause drag. You don't see any torpedoes with huge sails on the dorsal part of the torp.

Any thing that sticks out from the sub's surface will create drag. There is friction and turbulence in this area that holds the sub back and slows it down.

If the Navy wants to save fuel and make our subs go faster then that should be a substantial reason to get rid of the sails.

Unless the sub spends a substantial amount of time on the surface where the command can see the sky with naked eyes and not get their feet wet is the main reason for the mission I see no other reason for maintaining the sails on our subs.

And if they do maintain the subs why don't they streamline them better. They have tried to streamline the front or anterior part of the sail but they left the posterior (rear end) part of the sail with no streamlining. They back part of the sail is where you get a lot of drag created and this slows the sub down tremendously. It reminds me of the US Highway with all the truck cabs having the wind deflectors on top of the truck cabs but with nothing at the rear end of the trailer to smooth the transition. The rear end of the trailer is just a flat transition of 90 deg and there is considerable amount of air turbulence at the back end of the trailer while going 75 mph down the freeway. A bullet shaped cone device attached to the rear end of the trailer would prevent that drag effect and thus increase the fuel mileage on the rigs by a factor of at least .50. Think how much fuel that would save the US economy every day. Think of all the tractor trailer trucks driving our highways each day.

Look at the nose end and tail end of the US subs. Or for that matter any submarine in service today. They have a smooth transition. Look at the nose and tail sections of any airplane. You then see that they are very aerodynamic in shape and form. There is a reason for that.

Further more look at the way nature designs it's animals that fly or swim. They are all very aerodynamic. We take many of our modern designs from Nature. Take Velcro for example. It's just a copy of the lowly cockle burr seed getting caught on our hunting pants.

On a major combatant submarine (not a special-ops sub like ASDS), non-penetrating masts still need to be "faired" (streamlined) to protect them from hydrodynamic forces and reduce flow-noise.

As far as a "bomb bay" goes, how then would you wire-guide a torpedo? Once you shut the "bomb bay" door to clear datum and evade counterfire, your wire would be cut...

TG

According to ex submariners and Dr joubert submarine hydro dynamic expert who advises navies all over the world, a smaller low profile sail is alot better than a massive great big one.

Virtual reality goggles!! :rock: :rock:

... and a advanced periscope like goldorak said. And there is nothing to say the mast can't penetrate the hull form (housed in the hull instead of a sail). :)

The breifing above seperates the function of the bomb bay from torpedo launches.

The recommendations are actually advising externally housed torpedos for fast response (like externally housed CM on the SW).. The "bomb bay" is just a means for the sub to carry any and every type of auxillary vehicle, sensor, UUV, or UAV it wants without having to worry about cylindrical shape constraints.... even UUV "gliders" for example... essentially a big cargo hold. Torps would be launched with built in hull arrangements and probably wire assessorys built into the torp.

Right now, the only way for a sub to launch anything is through tubes with strict shape restrictions.

Most of what I understand about hydrodynamics comes from the upper lever fluid dynamics courses in college and this book.... http://www.subsim.com/phpBB/viewtopic.php?t=51686

The removing the sail really wouldn't be that big a effect on stability... the aft fins, bow planes, and weight arrangements can easily handle stability.

Acutally its mostly the fault of the sail that subs experience the undesirable roll effect/instability during high speed turns.

What'd you mean? I thought the SSGN conversions went supposedly smooth and successfully..

http://www.globalsecurity.org/milita...74-gallery.htm
http://www.globalsecurity.org/milita...ncedSail-1.jpg

http://www.globalsecurity.org/milita...ncedSail-1.jpg

Re: In the future, submarines won't have sails
 

Great care is taken to streamline the sail on a sub. If you look at the interior structure and the items that it has to protect/operate, you would see that it is just big enough to hold these items

It is rounded at the front and tapers at the rear. If you look at it from above it is a large cord symetrical wing. All screws and bolts are flush mounted to minimize any flow noises. There are hatches to close off any openings and the tops of mast & attennna's are as flush as they can be in the stowed condition.

If you go to to http://www.fas.org/man/dod-101/navy/...cmp/part06.htm
About half way down there is a top down pictcure of the 688,688i,726 & seawolf sail.

There is a great deal of difference in hydrodynamics vs areodynamics. If you look at a 688 underway, you will find that all linehandling hardware is actually non-visible. The only one you will see at the 3 chocks that are aft of the sail. These are carefully arranged to be directly aft and in-line of the sail. All other items actully rotate to disappear. Great care is made to make the hull as streamlined as posible. It has NOTHING to do with speed and EVERYTHING to do with reducing any flow noises. We have a sail because it has a job to do. It is as small as possible and still able to do that job.

As a sidenote: Did you know that the most dangereous time for a sub is on the surface when transitting to and from port? When they are making way on the surface they are dang near invisible EXCEPT for that sail. The way the bow wave flows it does a pretty good job of hiding the hull in a side view on the surface. They might look all impressive in an aerial shot, but from sea level one mile awaqy they are EASY to miss from the side. Remember, you have NO smoke or other propulsion sounds or visualy clue to tell you that they are there. Wave sound like waves onthe ocean until you get REAL close.

Once I had to meet the boat a few miles offshore and when it was answering a full bell and heading towards us you could barely see it. It got to within a half mile before you could KNOW what it what it was. I KNEW where it was coming from and had trouble spotting it. WHat about that a ship that does not know it is even there?

The sail is there to so that the OOD, on the surface, can navigate the boat safely and not have any collisions. A periscope might allow you to see, but it is NOT better than a set of eyes when looking for other items and ships in the water.

That picture posted is photoshopped we have all had a lengthy debate about it, seawolf hull akula sailish not real doesnt exist the virginia has the same sail as the seawolf its basicaly a seawolf just not as expencive.