semi-submersible fast attack craft..

[wawa]

hii..i'm doing on the preliminary design of the semi-submersible attack(SSAC) craft...for my degree thesis...the requirement of the SSAC are to operate in to mode that are the surface planning mode at 45knots and semi-submerged mode at 10knots...i'm quite headache on how to start....do somebody thinks it's feasible if the catamaran or swath concept to put into the design...the hull form and the ballast system are what to emphasis...it will be great if somebody would have some reference or links related to this...thanks

[SailDesign]

Semi-submersible
Fast

Pick one.....

[SailDesign]

OK - that was facetious, even if it amused me briefly.

Seriously - I wouldn't like to be in a fast cat that had the draught to operate in semi-sub mode. Too far above the water surface for my liking.
Now, I'm sure yipster could design us up something with telescopic legs.....

Steve

[wawa]

Originally Posted by SailDesign

OK - that was facetious, even if it amused me briefly.

Seriously - I wouldn't like to be in a fast cat that had the draught to operate in semi-sub mode. Too far above the water surface for my liking.
Now, I'm sure yipster could design us up something with telescopic legs.....

Steve

actually the ship is require to semi-submerged in order to become 'stealth' to any form of detection..to quietly penetrate into enemy territorial...i'm not sure what did you mean by telescopic legs...

[SailDesign]

Telescopic legs are legs that can be made shorter or longer as desired.

[Jeff]

Hi wawa - you've peaked my curiosity with all the questions about various types of fast attack vessels. What exactly are you working on?

[wawa]

I'm trying to start from the feasible hull form...so i'm seeking details on the fast patrol and semi-submerged craft...below is the background of the SSAC:

"Current security scenarios emphasize on the need for rapid reaction force as well as the ability to penetrate into strategic location whilst reducing the risk of detection. Special forces may need to be delivered into or evacuated from deep enemy territorial. As such, there is a strong requirement for specially designed marine craft that can travel at high and at critical situations move undetected.

The SSAC is designed as a novel craft which operate under 2 conditions. In the normal mode, it is a fast planning craft having speed up to 45knots. In the semi-submerged mode, the craft is ballasted so that most of the hull is submerged, leaving essential portions above the surface. Due to its small portion and stealth design, the boat should be invisile to the radar and infrared sensors in this condition. The speep will be reduced to 10knots in this condition. Since the vessel is not fully submerged, problems normally associated with the design and construction of submarines do not arise. It is expected that the craft can be built and maintained using current technology available locally."

the output will be a preliminary design lines plans, model, powering prediction.etc...

[Morgig]

An old lecturer of mine Ray Harvey won the concept boat awards this year with the design of a fast sports boat that also functions as a open submarine. The concept boat web site does not have much in the way of detail but it may be interesting to you.

http://www.conceptboat.com/winnerprofiles.asp

[dkubiak]

I'm not sure how semi-submerged would evade detection. Most important harbors are monitored by means other than visual - i.e. the movement or heat from the craft would be detected.

Dan

[yipster]

recall i didnt react sooner couse i didnt know what area could be attacked from location hgfhfg
here a picture of a national sucurity platform stealth SWATH but think Morgig response comes closer to your quest?

[jehardiman]

I think you should stumble along on your own for this one, after all, it is your thesis. And remember that for an engineer it is as important to know what you can't do as well as what you can.

There is one craft I know of that could meet the requirements, the SBS operate it if I recall correctly. But a lot of decisions that you make on hull form are not going to just be based upon the criteria you have given above. There is range (in all its forms), endurance, capacity, support and transport, acoustics, non-traditional signatures, threat capability, etc. Just because it's state of the art doesn't mean that it's not useless.

You're going to have fun.

[djackson99]

Hi wawa

Not sure I can be much help, but I sure would like to read your paper when you're done. I am currently building a surface planning dry ambient submarine, and you’re welcome to have a look. My web site is www.submarineboat.com My goal is to build it for under $15,000 a bit under the Navy's budget You should also look at the Surface Planning Wet Submersible that STIDD Systems is building for the Navy.
See: http://www.sotech-kmi.com/archive_article.cfm?DocID=123
and http://www.specialoperations.com/Navy/SPWS/

Best Regards
Doug Jackson

[Stewart Davies]

Originally Posted by wawa

I'm trying to start from the feasible hull form...so i'm seeking details on the fast patrol and semi-submerged craft...below is the background of the SSAC:

"Current security scenarios emphasize on the need for rapid reaction force as well as the ability to penetrate into strategic location whilst reducing the risk of detection. Special forces may need to be delivered into or evacuated from deep enemy territorial. As such, there is a strong requirement for specially designed marine craft that can travel at high and at critical situations move undetected.

The SSAC is designed as a novel craft which operate under 2 conditions. In the normal mode, it is a fast planning craft having speed up to 45knots. In the semi-submerged mode, the craft is ballasted so that most of the hull is submerged, leaving essential portions above the surface. Due to its small portion and stealth design, the boat should be invisile to the radar and infrared sensors in this condition. The speep will be reduced to 10knots in this condition. Since the vessel is not fully submerged, problems normally associated with the design and construction of submarines do not arise. It is expected that the craft can be built and maintained using current technology available locally."

the output will be a preliminary design lines plans, model, powering prediction.etc...

The design you propose will maximise signatures of the wake and sound types. Wake is a major target for some types of radar and the deep hull will maximise the sound entering the water. ( Just what the sub guys like for easy kills.)

I recomend that you look at a SWATH type unit. If you shape the out of the water part right, it will have so little radar return that it will be invisable for all intents and purposes. You could use the Lockheed Seashaddow as a starting point. I have seen plans for high speed types, but think that deployable hydro foils would probably meet your speed requirement better. I would also rethink your speed requirements as a slower speed would increase range substantialy. You might try a range/speed traid-off study to find the best combo for most customers.

In iether case, the intigration of sensors and weapons will be your biggest headake.

Please excuse my spelling, Dyslexia!

Sincerely, Stewart.

[tspeer]

Do you have something in mind like Lockheed's CHARC?

[yipster]

another fast submersible or what?