[PSUBS-MAILIST] Looking at starting up a Submersible project

Tue Nov 22 21:14:41 EST 2016

Brian,if you Google motor controller on image search you'llsee that most of them, especially the larger ones, havelarge capacitors. They are usually on the input for smoothing out the current spikes you get on starting or from PWM.Alan

      From: Brian Cox via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Wednesday, November 23, 2016 2:40 PM
 Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

Alan,  Why do your motors need capacitors ?   Isn't that only for starting the motor?   seems  like a shaded pole motor would not need a capacitor . Brian

--- personal_submersibles at psubs.org wrote:

From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project
Date: Tue, 22 Nov 2016 21:22:55 +0000 (UTC)

Ludwig,
the semi-dry is like a bowl that is turned upside down with air trapped
in it. So not a lot of structural strength needed other than to support the
lead you are going to need & scuba tanks. All the electronics will need to be 
water & pressure proof. It is mainly the large capacitors that are vulnerable
to pressure & you find these predominantly in the motor controllers. Don't ask me
what pressure they fail at, I have just read that from other posts, & all 
capacitors are not the same.
There are those little scooters that just keep your head dry that could be
regarded as a semi-dry. 
I would be worried about a runaway situation with a semi-dry; where you
couldn't keep the air volume at the correct level & as you descended it would
compress even more. I guess you have vertical thrusters to counter that.
Not a lot more strength required for a dry ambient. A dry ambient will need
a conning tower, as with other submarines. If you build as per my design or
Cliff's R300, you will find it hard to get in without taking in water in
mildly rough conditions.
Alan 

      From: via Personal_Submersibles <personal_submersibles at psubs.org>
 To: personal_submersibles at psubs.org 
 Sent: Wednesday, November 23, 2016 8:35 AM
 Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

Thanks for the information Alan!
I think I'm going to go with the dry ambient design.  Also since I will be working at a dive shop, I would be able to get the regulators at a discounted price. (I'm currently in training to become a dive instructor)
Is the only difference between a dry ambient and semi-dry is that you are not going to be seating in water with the dry ambient or is there also a structural difference?
-Ludwig

-----Original Message-----
From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Tue, Nov 22, 2016 12:40 pm
Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

Ludwig,On my dry ambient I have 2 octopus regulators ( octopus are cheap & don't free flow)attached to a through-hull outside my hull. I extended the exhaust ports down to stop water coming in.With the life support air flowing in at 20 liters a minute, this tends to equalize the hull,& any overpressure goes out the regulator exhaust ports. Supplementary air is automaticallyprovided by the regulators. There are other ways that people use.I can elaborate if you go that path.Alan

      From: via Personal_Submersibles <personal_submersibles at psubs.org>
 To: personal_submersibles at psubs.org 
 Sent: Wednesday, November 23, 2016 5:01 AM
 Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

The easiest solution would be to just build a wet-sub!  
Any idea on how they maintain the air volume?  When scuba diving, you just manually inflate your BCD but I have a feeling those sports sub do something different.
How does a dry ambient regulate the inside air volume?
-Ludwig

-----Original Message-----
From: Alan James via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Mon, Nov 21, 2016 11:57 pm
Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

Ludwig,I don't know anyone that's built one, but Tim in Vancouver owns a semi-dry sports sub. You enter from underneath (& get wet) & the topof your torso is above water. It has the advantage of being lighter than a dry ambient,but is more complex in that you are sitting in a bubble that continuallycompresses as you descend & expands as you ascend, & needs to be kept at it's initial dive volume to maintain the same level of buoyancy.Most are built out of fiberglass. Alan

       From: via Personal_Submersibles <personal_submersibles at psubs.org>
 To: personal_submersibles at psubs.org 
 Sent: Tuesday, November 22, 2016 5:08 PM
 Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

I think all of you guys made some very good points and I do plan on visiting Scott in the next few weeks.
I think what I will do is go the semi-dry sub route.  Have a mix between a wet and a dry ambient sub!
Has anyone here built a semi-dry sub?  What building material should I use?  Should I go with steel or fiberglass?
-Ludwig    

-----Original Message-----
From: Douglas Suhr via Personal_Submersibles <personal_submersibles at psubs.org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Mon, Nov 21, 2016 9:53 pm
Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

Welcome to PSUBS Ludwig! You will definitely find some awesome, informative people here who can help you answer questions and make design / fabrication decisions along the way. If possible, a visit to Scott Waters is definitely recommended.  
Bear in mind that I am a novice PSUBBER, but I'll give you my two cents on your situation: If you are a scuba diver and comfortable diving ambient, go for a wet or semi-dry sub, not full on dry ambient. I say this because there are still an infinite number of learning opportunities with a wet sub, but you aren't dealing with the ballast weight needed to sink an entire air-filled hull. If you really want to go dry, go one atmosphere. 
If you are going to be leaving the states in 18-24 months, a wet sub (like a DPU / scooter or a bubble sub) seems like it's just the ticket... whatever you decide, good luck on your journey. Don't forget to pop back on to the list occasionally and give us updates on your progress.  ~ Douglas S.  
On Mon, Nov 21, 2016 at 3:59 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Ludwig,I believe Brent wasn't that happy with his dry ambient, & thereare aspects that I didn't like, like his large square hatch.You are only ambient at a certain point between the bottom ofyour hull & the top. Everything below this point is under external pressure& everything above is under internal pressure. This can put a lotof internal force on the hatch. To visualize it, mentally flip your sub upsidedown and fill it with water to ambient point. The weight of water on your hatchwill be equivalent to the internal air pressure on it when diving. There are modifications to the batteries that need doing if you want themin the hull, as they typically crush at about 15ft.You have 20 liters of air per person flowing in to the hull for life supportplus the air for equalization, which is 4 x the volume of your sub at 100ft.So a lot of air needed. You need to watch that any electronics can handle the pressure you arediving to. I made an ambient that is unofficially the World's smallest submarine as a model for a 1 atm. http://www.psubs.org/projects/ 1235435392/ambientsub/I can help you if you are set on a dry ambient.Regards Alan

      From: via Personal_Submersibles <personal_submersibles at psubs. org>
 To: personal_submersibles at psubs. org 
 Sent: Tuesday, November 22, 2016 8:52 AM
 Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

I was talking with Scott and he also mentioned that it would take longer then two years to built a 1 atm sub.
What I'm looking at now is building a dry ambient submarine.  I would learn a lot with building it plus when I move aboard, I can set down and start building a 1 atm sub.  I found a 3 man dry ambient submarine built in New Zealand by Brent Shaw that I'm looking at down scaling for one person.
I should also probably mention that I'm also a scuba diver so a dry ambient submarine won't be much of a problem.
-Ludwig

-----Original Message-----
From: Alan James via Personal_Submersibles <personal_submersibles at psubs. org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs. org>
Sent: Mon, Nov 21, 2016 1:28 pm
Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

Hi Ludwig, welcome.If you only have 2 years you won't have enough time to finisha 1 atmosphere submarine. Small or large, it will still need a similar amount of time. I built a dry ambient, which was a great learning experience, but is not as safe as a 1 atmosphere.    Take up Scotts offer of a visit, you will learn a lot from that.Also read through the "Busby manned submersibles" book. There is a link on the Psub site o an online version, but mostpsubbers end up buying a copy of it.Cheers AlanNew Zealand

      From: via Personal_Submersibles <personal_submersibles at psubs. org>
 To: personal_submersibles at psubs. org 
 Sent: Tuesday, November 22, 2016 3:55 AM
 Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

That really doesn't help me much because I'm planning on moving across the pond in around two years!
I'm looking at a small project that would teach me all the systems so when I move across the pond, I would like to build something along the Euronaut size or a tiny bit smaller.
I've also debated if I should do a wet-sub instead because if I go that route, I wouldn't have to build a pressure hull.  That would only limit me down to 130 foot allowed for recreational diving.
-Ludwig

-----Original Message-----
From: James Frankland via Personal_Submersibles <personal_submersibles at psubs. org>
To: Personal Submersibles General Discussion <personal_submersibles at psubs. org>
Sent: Mon, Nov 21, 2016 8:44 am
Subject: Re: [PSUBS-MAILIST] Looking at starting up a Submersible project

I think emile has a small ish boat requiring refurbishment for sale?  Probably worth the cost of shipping it over the pond to not have to build from scratch.
On 21 November 2016 at 13:51, Brian Hughes via Personal_Submersibles <personal_submersibles at psubs. org> wrote:

I know of an original VAST boat someone is trying to sell out here on the East Coast.

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