I think you mean changing the propellers pitch dean! J “sharpening” it can actually reduce the propellers efficiency and also if done incorrectly it can put the prop out of balance! International and Norcoat/Norglass are both good marine brands as far as 2 part polyurethane paint goes… Many psubs aren’t in the water long enough to have barnacles and growth build up one the prop’s/hull to become a worry… I free dived underneath a 50 foot twin screw cruiser/boat/ship just before xmas to scrape some of the barnacles off the running gear, props and rudders…. (4 or 5 years since its last antifoul) Also while I was down there I found a 1 inch diameter mooring rope wrapped around one of the props…. The props were about 2 foot in diameter! J the imbalance created by the rope wrapped around the prop was causing a massive shudder/vibration to come back through the boat! And only on that engine… which is how the skipper figured out something was a miss with that prop/driveline.. in some places there were barnacles an inch thick!!!!!! Coppercoat ablative antifoul (also made by international paints) is awesome for moored vessels! As long as they don’t have any alloy in their hull’s/driveline… 10 years between antifouling! But if you use it on a boat with an alloy leg/drivetrain on it… dissimilar metals + electrolysis = no more prop/leg in a very short while… for a sub made out of steel and painted with 2 part polyurethane might not have too much of a problem! J From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Recon1st@aol.com
Sent: Sunday, 3 April 2011 11:54 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Paint.....Cheap or Proper? Brian I would think that sharpening the prop would also increase efficiency. It sure does when you are trying to get more speed. Hello everyone finally got some time to go thru emails and I see there are lots of topics to read, we just tuned up our small boat the 100 foot swift boat and scrapped the bottom and gear as we do every month well we were running a couple hundred RPMs slower than we should so I spoke to an engineer he said polish the prop and you will get it back and sent me this link http://www.propspeedusa.com/index..php?option=com_content&view=article&id=2&Itemid=3 so my thoughts where if this worked as stated would PSUBS benefit from it less friction means longer battery life between dive it might be worth looking into oh and BTW we took a green scrub pad to the props and shaft and got the 200 back and gained 150 on top so he was right Regards Brian V. Ryder CONFIDENTIALITY NOTICE: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information or otherwise be protected by law. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of kocpnt tds.net
Sent: Monday, March 21, 2011 11:16 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Paint.....Cheap or Proper? Sorry, but I forgot about the Zinc. I actually did use it on my boat but forgot to mention it just now! On Mon, Mar 21, 2011 at 1:05 PM, <MerlinSub@t-online.de> wrote: Commercial ships use the way Vance describe.
First sandblasting, than zinx 98%-epoxy, than thick watertight 2k epoxy, than Polyurethane to make a nice and sun tight surface. All this paints are expensive - but there must be a reason that ships designed to MAKE money use it... ;-)
KSS Eurosub and the Euronaut goes the same way. Euronaut gets his paint some 8 years ago, still standing outside - no rust - not outside - not inside.. Yes I think there is a reason that the stuff is such expensive..
By the way only the small boxes are really expensive, special the one for sport boat using.. May ask a bigger yard/bridge building whatever company for remains..
But important as the paint ist the paint concept! How many layers, of which stuff, in
which thickness, and in which time windows.
vbr Carsten
<vbra676539@aol.com> schrieb:
>
> Jim and all,
>
> I agree about the use of best available coatings. On the exterior of Gamma and my K-350, I use a zinc coat on bare steel, hi-build epoxy over that as a strenghtening component and tie coat, and then polyurethane over that as the final coat. The polyurethane is able to take a harder whack without fracturing and doesn't chalk in the Florida sun. The combination is getting on toward bulletproof.
>
> If you want to do it up really well, there are Dimetcote vinyls available. Those are milspec Navy coatings. Expensive. $600+ per gallon, but it is really good stuff, as you might imagine. We used it by the truckload at Perry. But paint technology has advanced since then, so I don't know what the very best is these days.
>
> There are less expensive and labor intensive methods for the interior, however. Gamma's ABS specs for interior coatings call for Rustoleum over zinc, and that works very well. Nine years in storage and the coating only has a very few pinhole issues to show for it. That isn't a guess. I'm looking at it right now.
>
> The zinc undercoat is critical. After that, you want something that seals. That sounds patently obvious, but keep in mind that this stuff is slathered onto a pressure vessel that flexes under pressure, and works in a hostile environment. You skimp on it at your peril.
>
> Vance >
>
>
>
>
> -----Original Message-----
> From: JimToddPsub <JimToddPsub@aol.com>
> To: personal_submersibles <personal_submersibles@psubs.org>
> Sent: Mon, Mar 21, 2011 10:30 am
> Subject: Re: [PSUBS-MAILIST] Paint.....Cheap or Proper?
>
>
> The last time I worked extensively with coatings was 1983. We were using two-part polyurethanes that cost $250 USD per gallon at that time. Epoxies were considered older technologies that were becoming obsolete, however I think the term "epoxy" is being used generically to denote any type of two-part coating (color and catalyst or hardener).
>
> This is one of the last places I would try to save money, and I would spend just as much on interior primers and coatings as exterior for two reasons:
> 1. Preventing corrosion is a lot better than trying to cure it, and having to do that (and redo) the inside the sub can be a bear.
> 2. After an operation, I can wash down the exterior with fresh water and whatever else I chose to use. That's not an option with the interior.
>
> I've also wondered about spraying the entire exterior with a wax several hours prior to a mission but haven't investigated that. Seems reasonable.
>
> Jim
>
>
> In a message dated 3/21/2011 8:15:34 A.M. Central Daylight Time, Alec.Smyth@compuware.com writes:
>
> The first time I sandblasted and painted Snoopy, I put lots of coats of expensive epoxy on the outside, but had this same exact thought about the inside. That surely won't get wet, therefore cheap and ordinary paint should do! Well, when Snoopy was in Florida the humidity was 100%, the temperature was something ridiculous, and climbing in and out even splashed a little salt water inside. With the combination of those three factors, when I was being towed out to a dive site the inside rusted so fast I could actually see the rust move. I mean that literally, you could see it popping up from under the paint, rather like a paper towel that has been laid over a counter that's sprinkled with water.
>
> I still don't use as expensive a paint on the inside as the outside, but one paint I've found is economical yet tough is a two part epoxy for painting garage floors. It's very thick, giving really good coverage, and resistant to abrasion. The downside is there aren't any rust preventers in it because it's intended for concrete, so you want to spray a base for metals underneath.
>
>
> Best,
>
> Alec
>
>
>
> The contents of this e-mail are intended for the named addressee only. It contains information that may be confidential. Unless you are the named addressee or an authorized designee, you may not copy or use it, or disclose it to anyone else. If you received it in error please notify us immediately and then destroy it.
>
> From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of James Frankland
> Sent: Monday, March 21, 2011 6:06 AM
> To: personal_submersibles@psubs.org
> Subject: [PSUBS-MAILIST] Paint.....Cheap or Proper?
>
>
>
> Hi All,
>
> Im going to paint the inside of my battery pods today. As theoretically, the insides should not get wet, i was thinking of using just a normal metal paint like Hammerite or something. A straight forward paint that you would use to paint outdoor railings and things with. Do you think this will be ok or should i go for the "proper" 2 part epoxy marine primer? Its just really expensive.
>
> What do you think?
>
> Thanks
> James
>
>
>
>
>
>
>
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