Forward water tank outlet

Google Mirror
1

(from Google Group posting)

Peter Grabow pkent42@gmail.com

Hi All,

I am planning on replacing my 30U’s 58 gallon forward water tank, and my holding tank this Spring, as they are the original aluminum tanks. The holding tank has not presented any issues as of yet, but as it is 38 years old I figured do it now before it has an issue.

The forward water tank has had pin-hole leaks over the years, and I have pulled the tank out, cleaned out the aluminum sand, patched the pin-holes, and put the tank back in place. This has worked well, but it is time for a new tanks from the Nonsuch.org tank program.

Question:

The 1/2" outlet (“drain”) port on the original tank is at the forward end of the tank. Makes it difficult to get the last gallon of the water or anti-freeze out of the tank when winterizing or commissioning, as that part of the tank is slightly ‘up-hill’… my guess is that it is connected this way to help keep sediment/debris away from the “drain” port?

The new tank schematic shows 1/2" drain ports at both the forward and aft ends of the tank, so optional hose attachment… is there a disadvantage to using the aft port instead of the forward port? I am figuring that the aft port attachment point will allow for easier removal of almost all of the water when necessary.

Thoughts/experience?

Oh - and the tank program says 2-3 weeks to receive the ordered tanks… is this fairly accurate? I am trying to hit a window between being away and moving my boat from it’s current location to it’s new Spring/Summer berth in Stamford, CT at the beginning of April.

Thank you,

Peter Grabow
S/V CAKE WALK III
1987 30U 430
Jersey City, NJ

2

from Nonsuch water tanks - issue with new one 02/2023

(see Brian’s post on welded polyethylene - it may be of value)

JohnS

ivatt260@gmail.com

Feb 15, 2023, 9:23:18 AM

Hello all;

Ordered new tanks a while ago now; yard did not get a chance to install in 2022. They are installing now, and upon unwrap, there’s an issue with a hole in one of the threaded inserts.

Anyone had an issue with these tanks?

Anyone have an idea for the way forward?

Two pictures from the yard crew attached.

MRMB6292
MRMB62921920×2560 163 KB

SRDT0232
SRDT02321920×2560 144 KB

John NS26C 046 Bath, ON.

SRDT0232.JPG

Barry Connell's profile photo

Barry Connell

envirocom50@gmail.com

Feb 15, 2023, 9:28:25 AM

These tanks are polyethylene, the same plastic as hot glue. Gently pass a flame from a propane lighter over the hole or gap to prepare the surface, then plug it with hot glue. Worked for me1

Barry Connell

N36 Nocturne

Newburyport, MA

Brian M. Godfrey's profile photo

Brian M. Godfrey

brian@wildbirdshop.com

Feb 15, 2023, 2:45:16 PM

First question; Yours look like welded polyethylene. I don’t know if they were from the same manufacturer, but the Tally Ho project had similar experience:

Having worked in manufacturing engineering in my earlier years I find it unconscionable that tanks with leaks would ever be shipped and I’m not sure I’d trust the rest of their work to hold up. You might want to pressure test it (just a couple of PSI!) before installing to ensure there are no pinholes. I think they showed a process for testing in that video.

Second question; Hobie makes kayaks from polyethylene and they sometimes take a beating. I run a volunteer organization in which kayakers remove fishing gear and litter from lakes and shorelines. Our boats are treated like work boats, get a lot of abuse and sometimes need repair. Hobie sells a repair kit which I’ve used a number of times (and need to use again if I can find the latest pesky leak!) Here is a link where you can buy one:

That welder has a handy feed-through hole for the plastic material, lots of color choices, but a blunt tip. Here is a different one with out the feed hole, but with a pointed tip that might be better working into a corner, though that does not look like an issue for you.

You will notice that both of these kits come with stainless reinforcing mesh. I think I would be tempted to cut that to encircle the whole fitting flange. You can actually heat the mesh with the iron and push it into the underlying plastic. Then add more plastic to cover it and - very important - smooth and feather out your edges to remove stress points. Remember that something is going to be screwed into this and connect to a hose which will vibrate.

I’ve never done a fuel tank, so no guarantees, but I think that would give you a very long-lived repair. I used this method to repair a crack where my seat rests in the kayak (these kayaks have removable lawn-chair like seats) and it has lasted for three years of my way too heavy butt falling into it, sitting in it, and squirming around as I pedaled or leaned over the edge to work. Probably more stress than this fuel tank joint would ever see.

–Brian M. Godfrey
br…@wildbirdshop.com

3

On Saturday, February 8, 2025 at 4:20:15 PM UTC-5 Joe Valinoti wrote:

I don’t see a problem with using the aft drain port. I’m assuming that you have a strainer and a large filter like I do that would catch anything. I’ve had troubles with the forward one on my tank due to the sharp turn it makes.

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

4

Peter / Joe

I’m glad I got to read the last two posts about the forward water tank in a N30U.

That will be my next tank replacement when my boat is in the water again this spring.

Right now I’m pulling my old aluminum holding tank and replacing with a tank I bought with the INA Tank Replacement program. It came in about 6 weeks but had to ship from California so not too bad.

Thanks Joe for pointing the way for us.

Brian Cayer

Spirit~Wind

N30U 419

Westbrook, Ct.

5

Hi -

As I am preparing to install the newly received holding and forward water tanks, I have a follow-up question:

What sealant is best for the threads of the male fittings I will install on the tanks?
I have purchased new Marelon fittings as I wasn’t sure I’d be able to remove the old fittings. And the vent openings on the new holding tank are larger than on my original tank.

It appears that 4200, or maybe 5200, was used on the original aluminum tanks and their Marelon fittings… is this acceptable for the new polyethylene tanks and Marelon fittings or is something else the proper way to ensure nothing leaks?

Thank you,
Peter Grabow
S/V CAKE WALK III
1987 30U 430
Jersey City, NJ (moving to Stamford in a month!)

6

Peter Grabow’s request for information on sealant for the polyethylene tanks came just as I was about to ask the very same guestions. The sealant I have is 4000 marine and the fittings are not marelon but schedule 40 and 80 and stainless steel reducer for the vent line. My question is that acceptable for a holding tank? Or should I get Marelon fittings and use something else for sealant?
Thanks,

Brian Cayer
Spirit~Wind
N30U 419
Westbrook, Ct

7

Hi,

As previously mentioned, I believe the correct sealant to use is 3M 4200 or Silkaflex 291, don’t use silicone or Teflon tape. Unless your tube of 4000 is pretty new, I’d buy a new tube given this is a somewhat mission critical application, at least the holding tank is. My boat has both Marelon and Sch 40/80 fittings. Ronco says not to use metal fitting directly on the tank.

Here is link to Ronco’s website info on…

Pre-installation tank cleaning: Sanitation of Plastic Tanks – Ronco Plastics

Insallation: https://ronco-plastics.com/installation-info/

You may also want to visit the Marelon website to see what sealant they recommend. There are some instances where some sealants are not compatible with certain plastics.

Cheers,

Don

’87 NS30U #369 - Breezin’

Vancouver, BC

8

Schedule 40/80 PVC? We’ve probably got that all over our boats, but I’d stay away from PVC on the holding tank. PVC becomes brittle when cold and can crack from stress or vibration. Even the thermal expansion and contraction of tightly restrained piping or tank could stress it enough to crack it. I know this through painful personal experience, not just some vague theory of mine. It’s not a really high probability, but if that happens while you are laid up for the winter you won’t know until you get some stinkwater in the bilge. And the broken fitting will be glued in with 4200. Then you’ll really wish you’d used Marelon.

Brian Godfrey

9

Your are right, I had a Sch 40/80 vent fitting on holding tank crack. Luckily it was easy to fix, I replaced it with nylon fitting and 4200. Holding tank discharge also Sch 40/80 was weeping a bit, previously installed with Teflon tape. I replaced it with Marlon fitting and 3M 4200.

Don

10

Hi Don,

Thank you for your input and the links for the pre and installation guides from Ronco. Very helpful!

Now, if the 25-35kt winds would subside, and the temps would remain in the 60’s around here, I can get to work!

Regards,
Peter Grabow

11

Yes thanks Don.
Good info.

Brian Cayer
Spirit~Wind
N30U 419
Westbrook, Ct

12

Hello All -

Following up on the new tank installations:

Holding tank: Tank went in with no issues, and replaced all fitting and hoses. Only adjustment was the vent hose on the new tank is 1" port, and the original was a 7/8" - I used a reducer connector to clamp the new 1" hose to a short piece of the smaller hose I left attached to the thru-hull vent. Worked well and since this is only an air connection there is no concern about liquid leakage.
Upon testing all works well with no leaks.

Forward 58 gallon water tank - I ditched the idea of replacing all of system water hoses as there was no easy way to connect the new water hose (PVC hot/cold tubing)) to the original gray pipe hoses and the valves, and I didn’t want to do this big project at the moment. Got the new tank fittings sealed in place and a few days later connected the hoses. Nice to have the full complement of water available again!

Again, the input was very appreciated!

Peter Grabow
S/V CAKE WALK III
1987 30U 430
Stamford, CT - SHYH

13

I look forward to seeing you out there sailing Peter. At least I know you have a good working head and a good water supply. Well done.

Brian Cayer
Spirit~Wind