scaling down a submarine?

[PAR]

Originally Posted by tugboat

. . . p.s. i am not concerend no pros have reposponded-i represent a threat to them-but of course . . .

A few pros have responded early in the thread, but have long since lost interest in someone that doesn't listen to reason. We see this sort of thing frequently, fortunately most don't have the money to drown themselves with a completed project.

Would you fly in an airplane or ride an elevator to the 50th floor, if designed by someone with your unwillingness to pay attention, to the reasonable and rational thoughts of folks, that do this for a living? The calculations aren't particularly difficult (tedious, but not hard), nor the engineering, if the depths are relatively shallow, but you seem to desire ignoring the basic engineering principles, that allow rational people's trust airplanes and elevators.

Stay in the waste deep end of the pool and good luck . . .

[Mr Efficiency]

Tugboat must be an eccentric multi-millionaire of small stature, with strong nerve and too much time on his hands. Otherwise I don't understand the motive behind it.

[hoytedow]

Originally Posted by Mr Efficiency

PAR has missed his metier in life, a career in the diplomatic corps.

Famous last words: "Hey, look what I can do!"

[tugboat]

yep same old same old --people who have nothing to input- and nothing intelligent to contribute-other than giving vague analogies and not looking at the possibilites.. and trying to throw rocks at dream...people who know as little about what im doing as i know what thier high school years were like growing up...why even bother--i should have learned to just stay off this forum --beam me up scotty theres no intelligent life down here...

[hoytedow]

I'm sure your sub will be better than this one: http://www.youtube.com/watch?v=ykmknR3_P8I

[tugboat]

A few pros have responded early in the thread, but have long since lost interest in someone that doesn't listen to reason. We see this sort of thing frequently, fortunately most don't have the money to drown themselves with a completed project. **** Par--its isnt me that isnt seeing the reason here...its people who need to cling to their security blankets of theory which has no substantial bearing in real world applications...btw which SUBMARINE pro's are you refering to other than the one person who stated he was(and thats even debatable)

Would you fly in an airplane or ride an elevator to the 50th floor, if designed by someone with your unwillingness to pay attention,
**** yea PAR-sure- (sarc) i just didnt think about any design parameters i just wanted to make sure the vessel out of paper mache--further lets have a discusion if you dare---

i bet i know nearly as much as you about design at this point-- and without a doubt more than you about submarine vessels!!! so dont lecture me that i dont listen or that i surely will fail...you dont have any better clue.. that what i am doing will fail or succeed--you dont know so offer somehting of value related to my project or dont bother wasting your time on trying to sack my project--i could tell you that your deisgn for the 39 ft yacht you had- has some serious flaws btw--i looked into it and i can say there are things that could have been improved for sure on that one!!..so- i guess we are even...


to the reasonable and rational thoughts of folks, that do this for a living-
******yes- and who follow things to overcomplication...its simple par- build a strong pressure hull --it will work...this means overbuilding just to be sure...it adds necessary weight for ballast and it ensures proper strength...proper dive plane and control surfaces...

? The calculations aren't particularly difficult (tedious, but not hard), nor the engineering,***** once again you assume that i havent done any calcs...


if the depths are relatively shallow, but you seem to desire ignoring the basic engineering principles,***** based on what PAR???


that allow rational people's trust airplanes and elevators.Once again--please be specific -since you know so well how i have ignored basic engineering principles..please tell me which ones in specific detail? if you know so much teach me! chances are i could teach you a thing or twoabout sub design...btw i have also consulted engineers who know more than you on this matter.

Stay in the waste deep end of the pool and good luck . . .***sure again--thank god we have someone of your expertise on here to inform me it surely will fail ok -yes illl make sure i dont build it based on your opinions and lack of concrete supporting evidence and mathematical model and numbers that my sub will fail...

diving depth limited to 200 ft.

[tugboat]

Originally Posted by hoytedow

I'm sure your sub will be better than this one: http://www.youtube.com/watch?v=ykmknR3_P8I

sorry hoyte-- apparently that vid isnt available in my country--or so it tells me--b ut i have seen some bad ones on youtube--and yes true i hope it turns out better--but im pretty confident now..im off to loft out more frames today while the weather is good...the tedius -time consuming process of rolling the rebar...

[tugboat]

Originally Posted by Mr Efficiency

Tugboat must be an eccentric multi-millionaire of small stature, with strong nerve and too much time on his hands. Otherwise I don't understand the motive behind it.

thanks for the neutral post- ill explain--
1. a sub is far more efficient than a surface vessel needing less hp and using 1/8th of its time on electricity making it a hybrid vehicle.

2. it can dive from storms and is safe anchored anywhere due no windage or freeboard-
3. its completely sealed and cant take on water in a storm
4. it has less motion to cause seasickness
5. it is able to run in under bergs
6. a sub is actually less coslty than a yacht of the same size
7. it offers both surface running views as well as submerged views of wrecks etc
8. needs no marina to moor
9. can drift dive in the gulf stream for free!
10. it offers a Nemo lifestyle
11. it has almost unlimited range in buying fuel in areas where its cheap such as argentina- i.e. 12 cents a litre...
12. pirate safe
13. its more fun in my opinion than a surface vessel-
14 there are many other factors such as ease of installation of engines- fitting out is less costly due to no need for masts, fittings, bollards, cleats, transoms, deck fitting hatches windows etc etc etc...
in ferro-cement medium there is virtually no condensaiton-fire proof,less maintenance than a steel hull- no need to evacuate pressure form temperature change-such as in steel9although i will have a bleed off valve for that purpose.
15- you can see more underwater.
16. more efficient due to larger props that can be used.
17 potential for very quick running especially underwater.
18- its more private-if you dont like where your moored cuz some idiots are too loud--dive a few feet and go to sleep

[Jeremy Harris]

Originally Posted by tugboat

thanks for the neutral post- ill explain--
1. a sub is far more efficient than a surface vessel needing less hp and using 1/8th of its time on electricity making it a hybrid vehicle.

2. it can dive from storms and is safe anchored anywhere due no windage or freeboard-
3. its completely sealed and cant take on water in a storm
4. it has less motion to cause seasickness
5. it is able to run in under bergs
6. a sub is actually less coslty than a yacht of the same size
7. it offers both surface running views as well as submerged views of wrecks etc
8. needs no marina to moor
9. can drift dive in the gulf stream for free!
10. it offers a Nemo lifestyle
11. it has almost unlimited range in buying fuel in areas where its cheap such as argentina- i.e. 12 cents a litre...
12. pirate safe
13. its more fun in my opinion than a surface vessel-
14 there are many other factors such as ease of installation of engines- fitting out is less costly due to no need for masts, fittings, bollards, cleats, transoms, deck fitting hatches windows etc etc etc...
in ferro-cement medium there is virtually no condensaiton-fire proof,less maintenance than a steel hull- no need to evacuate pressure form temperature change-such as in steel9although i will have a bleed off valve for that purpose.
15- you can see more underwater.
16. more efficient due to larger props that can be used.
17 potential for very quick running especially underwater.
18- its more private-if you dont like where your moored cuz some idiots are too loud--dive a few feet and go to sleep

As someone with some time in submarines on trials work, I'd say you really need to balance some of those points and look at them a bit more closely.

The risks are considerable, from unknown hull structural flaws causing hull rupture (even 200 ft is over 6 bar), through the issues associated with scrubbing unwanted gasses from the internal atmosphere in a controlled way, through to the very considerable technical challenges in making hatches and ports secure and leak proof without introducing stress raisers in the pressure hull. There are good reasons for boats having cylindrical pressure hulls with a teardrop non-pressure hull casing around the outside - worth considering, as it's damned hard to make a tear drop shape with good and known structural integrity, even for operation at just a couple of hundred feet.

Some of the pluses up in that list aren't quite right, either. Subs give a pretty nasty ride unless they are running below the wave affected zone (which means being around 20 m or so down, more if it's really rough). They have limited reserve buoyancy (in the UK we design for being able to surface with one flooded compartment, the old Soviet boats didn't even have this much reserve, hence, in part, their high serious accident rate).

Navigation is challenging. The INS required needs to be very sophisticated to give you a reliable nav system when you can't access GPS, LORAN or whatever because your submerged. Dead reckoning is very difficult, because sub-surface currents are rarely known or marked accurately on charts and they vary wildly from surface currents (they will often be in the opposite direction even).

Attitude control is far harder than it seems and is critical for operation close to shore, even on a 50ft boat. It's quite possible to have the bow or stern hit the bottom from vigorous trim changes, for example, and a sub has a high polar moment so once swinging wants to carry on.

Also it's possible to get a submarine out of pitch trim to the point where it cannot recover back to the surface from an over vigorous nose-down plane angle. What happens is that the rate of descent can result in a pressure increase that the tank blowing system cannot keep up with - meaning you keep on going down unless you have enough plane authority to pitch back up - the planes then become highly safety critical.

As for "seeing more underwater" I guess you've never been at depth and tried it! Suffice to say that down below a few tens of metres the vis is crap as a general rule. Around this part of the world, even in shallow water, the vis rarely exceeds a few metres.

I should add a qualifier - I absolutely hated being in a submarine, so much so I once paid my own air fare home rather than go back to the UK on the boat. It colours my views a bit...........

[Submarine Tom]

TB,

I admire your tenacity. If you're willing to die trying, then all the power to you. I take it you don't have any responsibilities, kids, etc.

Also, don't be jeopardizing any Search and Rescue resources my friend, they are a valuable asset not to be squandered.

My last comment would be: don't waste too much of your energy on defending your approach/style, just do it and post pictures, no gloating.

All the best, I can't wait to see the first crush depth test (unmanned of course)!

-Tom

[Boat Design Net Moderator]

It appears a second thread has been started here sub build underway christmas 2011 on the same topic, so let's continue the discussion there so as not to force replies to be duplicated. Thanks.