Aft tank draining

[Evan DeLucia]

I'm pretty sure I have a leak somewhere related to my aft tank. All valves for the other two tanks closed, my aft tank drains quickly triggering the bilge pump. I spend the a couple of hours trying to view the tank. Climbed into the rear locker - I'm not small! - but couldn't get to it. Any thoughts about how to diagnose and fix the problem would be much appreciated.

I hope everyone is enjoying a great start to the season!

[Marvin Isgur]

On Hull 5, the line runs just inside the port wall in the aft.  Remove the mattress.  Lift the Formica covered wooden panel by lifting on the finger hole. Mine had a loose connector a few years ago that just had to be pushed together. I bet you will see the water leak coming down once you remove the panel.

On Jun 24, 2026, at 8:20 PM, Evan DeLucia <deluc...@gmail.com> wrote:

I'm pretty sure I have a leak somewhere related to my aft tank. All valves for the other two tanks closed, my aft tank drains quickly triggering the bilge pump. I spend the a couple of hours trying to view the tank. Climbed into the rear locker - I'm not small! - but couldn't get to it. Any thoughts about how to diagnose and fix the problem would be much appreciated.

I hope everyone is enjoying a great start to the season!

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[Marvin Isgur]



[Marvin Isgur]

Sorry.  Typo. It’s Hull 3 and not 5 if that matters. 

Sent from my iPhone

On Jun 24, 2026, at 9:03 PM, Marvin Isgur <kir...@sbcglobal.net> wrote:



To view this discussion visit https://groups.google.com/d/msgid/catalina355/CC9537A9-1141-45F5-8B53-95EBB32DB478%40sbcglobal.net.

[bill pittore]

If that doesn’t work then you can get access to the whole aft tank by removing the wood panel as Jon Vez explains here:

Bill

To view this discussion visit https://groups.google.com/d/msgid/catalina355/D29FDD86-5C95-45D8-8840-62DAF3003547%40sbcglobal.net.

[Evan DeLucia]

I'll head out next week and pull the aft bed out to see if I can see the lines. Bill, when you mention pulling out the teak panel are you talking about the teak at the foot (port side) of the bed? I can't really tell from the photos.

[bill pittore]

Port side, correct. 

Bill

To view this discussion visit https://groups.google.com/d/msgid/catalina355/c19e4f4e-f582-4347-b322-99ca505194f0n%40googlegroups.com.

[Jon Vez]

Hey Bill & Evan,

I still lurk here, so if I can answer any questions, I’ll be happy to try, although my memory may be a bit hazy. Once you’ve done it, that panel will become removable for inspection/other projects as it’s the glued trim piece that needs to be separated.

Good luck!

Sent from my iPad

On Jun 25, 2026, at 10:02 PM, bill pittore <bill.p...@gmail.com> wrote:

Port side, correct. 

To view this discussion visit https://groups.google.com/d/msgid/catalina355/3144EDC8-3DA0-448D-ACDD-171D774D938E%40gmail.com.

[catalina]

Here are a couple pics I have.

Jeff Hare

To view this discussion visit https://groups.google.com/d/msgid/catalina355/1CBAEA16-2968-4658-9FF3-5FD294DE858A%40gmail.com.

[Walter Baransky]

You are really good. Just wanted to say!

To view this discussion visit https://groups.google.com/d/msgid/catalina355/1782483057166.2b124bdf66484175%40thehares.com.

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Regards,

Walter Baransky

[catalina]

Thx 😂,  

The whole time I was cutting that square opening on the back wall for the air conditioner I was installing, I kept thinking about my life choices... 😂  ...and how I was going to get Jon and Doe to buy back Solstice with big holes in it. 

I'm sure I still have fiberglass on me 2 years later. 

Jeff

Sent from my Galaxy

To view this discussion visit https://groups.google.com/d/msgid/catalina355/CABK9k49ggL08-FvWSt58KcAw%2BPN9P-pfSL2qJQ%3DeL-95VbzABA%40mail.gmail.com.

[Andy Karlin]

As long as we're discussing leaks, I have (salt) water coming into the compartment below the head of the articulating mattress just aft of the crash bulkhead; it pools around the base of the strut that raises and lowers the mattress, about 1/2" deep, but sloshing around the compartment when underway. Water also gets into the two compartments aft of the base of the vee berth bed, both port (where the transducers are), and, less often and with less volume, to starboard. Finally, about an inch or so of water gets in the forward main cabin bilge, and a little less so in the bilge compartment just aft. This leakage only occurs when underway, and has been happening over the last few months. Before then, the bilges were dry (I own Hull #2, and bought her, Prudence, in September 2024). Any ideas? I'm going to meet with my boat mechanic momentarily to make a dedicated attempt to figure this out.

To view this discussion visit https://groups.google.com/d/msgid/catalina355/1782485303670.7aa4f5a154a73fd9%40thehares.com.

[Charlie Wing]

Hi Andy,

Could it be getting in through one of the thru hulls for the transducers, not sure if you have a washdown pump (?). There are three on my boat in those two compartments in the Vee Berth cabin. These connect to the main bilge. Maybe when underway it applies more pressure. Assume the speed transducer is screwed in correctly, etc. & watertight?  

Charlie

Hull#20

Wing'n It

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From: catal...@googlegroups.com <catal...@googlegroups.com> on behalf of Andy Karlin <andrewk...@gmail.com>
Sent: Friday, June 26, 2026 12:37 PM
To: catal...@googlegroups.com <catal...@googlegroups.com>
Subject: Re: [Catalina 355:6188] Aft tank draining

 

To view this discussion visit https://groups.google.com/d/msgid/catalina355/CA%2BKgeUwd1xE%3DQbvv2tpb8wGeDq5U%3DzcAkW_b2bTTFWGRQnHPJA%40mail.gmail.com.

[bill pittore]

Hi Andy, 

If you search the Catalina 355 group for something like anchor locker leak you'll get a bunch of hits about this. Seems related to the anchor locker drains and/or how well glassed and sealed the locker is. 

Bill

To view this discussion visit https://groups.google.com/d/msgid/catalina355/CA%2BKgeUwd1xE%3DQbvv2tpb8wGeDq5U%3DzcAkW_b2bTTFWGRQnHPJA%40mail.gmail.com.

[Andy Karlin]

I actually suspect more than one leak and that one of them is a transducer in that compartment. I will update everyone on what I am about to learn from my mechanic in a few hours.

Sent from my iPhone

On Jun 26, 2026, at 9:53 AM, bill pittore <bill.p...@gmail.com> wrote:



Hi Andy, 

If you search the Catalina 355 group for something like anchor locker leak you'll get a bunch of hits about this. Seems related to the anchor locker drains and/or how well glassed and sealed the locker is. 

Bill

On Fri, Jun 26, 2026, 12:37 PM Andy Karlin <andrewk...@gmail.com> wrote:

As long as we're discussing leaks, I have (salt) water coming into the compartment below the head of the articulating mattress just aft of the crash bulkhead; it pools around the base of the strut that raises and lowers the mattress, about 1/2" deep, but sloshing around the compartment when underway. Water also gets into the two compartments aft of the base of the vee berth bed, both port (where the transducers are), and, less often and with less volume, to starboard. Finally, about an inch or so of water gets in the forward main cabin bilge, and a little less so in the bilge compartment just aft. This leakage only occurs when underway, and has been happening over the last few months. Before then, the bilges were dry (I own Hull #2, and bought her, Prudence, in September 2024). Any ideas? I'm going to meet with my boat mechanic momentarily to make a dedicated attempt to figure this out.

On Fri, Jun 26, 2026 at 7:48 AM catalina <cata...@thehares.com> wrote:

Thx 😂,  

The whole time I was cutting that square opening on the back wall for the air conditioner I was installing, I kept thinking about my life choices... 😂  ...and how I was going to get Jon and Doe to buy back Solstice with big holes in it. 

I'm sure I still have fiberglass on me 2 years later. 

Jeff

Sent from my Galaxy

-------- Original message --------

From: Walter Baransky <wbara...@gmail.com>

Date: 6/26/26 10:38 AM (GMT-05:00)

To: catal...@googlegroups.com, Walter Baransky <wbara...@gmail.com>

Subject: Re: [Catalina 355:6186] Aft tank draining

You are really good. Just wanted to say!

On Fri, Jun 26, 2026 at 10:11 AM catalina <cata...@thehares.com> wrote:

Here are a couple pics I have.

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<.EmailTempImageHEV_1782482995496.jpg>

To view this discussion visit https://groups.google.com/d/msgid/catalina355/CAFi%3DF1J2jWZxeReZZdrfvKt4ojH%2Bhx8SRXRSF%3DJAyrwRWardWQ%40mail.gmail.com.

[Marvin Isgur]

I had substantial penetration from loose bolts holding the forward stainless steel railing in place.  If you take a hose and run water onto the bolts on the deck, the underside that you see from the area forward of the bed should be dry .  If the underside is wet, they need to be pulled and reseated.  I had that exact issue and it has been fixed on Hull 3 for 10 plus years. 

Sent from my iPhone

On Jun 26, 2026, at 12:00 PM, Andy Karlin <andrewk...@gmail.com> wrote:

I actually suspect more than one leak and that one of them is a transducer in that compartment. I will update everyone on what I am about to learn from my mechanic in a few hours.

To view this discussion visit https://groups.google.com/d/msgid/catalina355/19C41AD7-7AF9-4E0C-811A-469A5000C0F6%40gmail.com.

[Andy Karlin]

All:

Thanks for the insights and information. After going through Prudence with my boat mechanic, Thomas, we discerned that most if not all of the water in the main cabin bilges has flowed back in from in the corrugated plastic tubing that leads from the forward main cabin bilge to the discharge port at the aft end.

As for the water in the v-berth compartment and port (transducer) and starboard bilges, it does not appear to be coming from the pulpit stanchions or toe rail screws. So, the source remains unknown. The amount of water that gets in after a typical four-hour day sail is a cup or less, so the leak does not prohibit sailing. Michael Green, former owner of Hull #54, sent me information regarding a similar issue he had. I will investigate whether his experience guides me to the leak source and an effective repair, and report back. 

Andy Karlin (Hull #2 - Prudence)

To view this discussion visit https://groups.google.com/d/msgid/catalina355/9D3F34AE-81E1-4F10-929B-B443473846C0%40sbcglobal.net.

[Andy Karlin]

Thanks for the insight, Marvin!

The railing turned out not to be the problem.

Instad, it was the issue Mike Green suggested: seawater leaching into the compartment beneath the anchor locker via the improperly sealed inner edges of the port and starboard anchor locker drainage holes.

Andy

On Fri, Jun 26, 2026 at 11:46 AM Marvin Isgur <kir...@sbcglobal.net> wrote:

To view this discussion visit https://groups.google.com/d/msgid/catalina355/9D3F34AE-81E1-4F10-929B-B443473846C0%40sbcglobal.net.

[Andy Karlin]

Thanks, Bill. It turned out the problem is the one Mike Green identified (water leaching in via the improperly finished edges of the anchor locker drainage holes.

To view this discussion visit https://groups.google.com/d/msgid/catalina355/CAFi%3DF1J2jWZxeReZZdrfvKt4ojH%2Bhx8SRXRSF%3DJAyrwRWardWQ%40mail.gmail.com.