Mystery Water in TAFG (Solved, Sort of)

[Christian Williams]

We're talking about very little mystery water. Maybe half a cup. But that spreads through two E381 bilge compartments a quarter-inch deep, and where's it come from? [The TAFG, "Tri-Axial Force Grid," is what Ericson calls the hull-stiffening structure introduced in 1980s boats.]

And are we sinking?

It's salt water. Yeah, I've been tasting bilges for 70 years. Not a goblet full, just tip of finger. Rain water isn't salty like that.

Today I found the source, perhaps exclusive to the E381, maybe not.

It is spray from my dripless shaft seal, after two hours motoring. The DSS probably had a bit of goop between the plates, which I just burped. I have a new DSS on order anyhow, to be installed during the haulout scheduled for March. I knew it was time.



Where does it exit in the bilge, which is 10 feet away?

[This post edited by me to remove incorrect information. See posts below.]

Well, on my boat it comes out a hole high on the TAFG wall. Of course it doesn't come out until the water level has risen a couple of inches, and then it just sorta oozes out when it fills up enough, just to make you crazy.

So, now I know the source of the half-cup of water sometimes in the bilge after motoring.

The TAFG is a great feature but does make for puzzling drainage issues.

 

[Kenneth K]

Interesting.

I've read discussions where people differentiate between "bilge" water versus water under the TAFG.

I've never thought it made any difference. Water may collect in the bilges and spill under the TAFG via the limber holes. Or, water can collect under the TAFG (like your leak, or leaky dorade vents in the stern as I have) and eventually wind up in the bilge via those same limber holes.

Bilge water; TAFG water, to me it's all the same.

 

[Christian Williams]

The difference is that the bilge pump doesn't remove TAFG water.

 

[Kenneth K]

But it does! Without a doubt.

When there is three inches of water in the bilges, there is about 3 1/8 inches of water under the TAFG (the unmolded hull/keel stub being slightly lower than the raised/molded bilge compartments). When a bilge pump kicks on, the water level at the bottom of the boat is lowered--in both (all of) the bilge compartments (as long as they are "connected" via limber holes) AND below the TAFG.

When the bilge pump stops, there is a small amount of a water left in the bilge compartments, and slightly more water that you can't see still below the TAFG.

If you have a bilge compartment that is "isolated," i.e., has no limber holes, then the above staments do not apply to that compartment.

I don't have a single bilge comaprtment that is as big as a 5 gal bucket (probably, all four bilge compartments put together don't amount to 5 gal of volume). After a long period of heavy rains, I've pumped 8 gal of water from the bottom of the boat. Most of the water is not actually "held" in the molded bilges, it's held against the inside bottom of the hull (i.e., below the TAFG).

 

[Kenneth K]

........As we know, boats with the TAFG, the grid structure introduced in the early 1980s, have a drip pan to isolate engine block spills. The molded-in pan sends such spills direct to the main bilge via a hefty tube that passes under the floors......

......However, the stuffing box (or DSS) is aft of the drip pan. So where does stuffing box leakage go?........It goes into a limber hole drilled halfway through the after lip of the pan.......Such water then moves "sideways" inside the transverse pan dam until it can find a route to the bilge........Well, on my boat at least, it comes out "stuff box drain" in the photo above..... This path of stuffing box water is unrelated to the path of engine drip pan contents. That drain is below it, and if you put a finger in the "stuff box drain" hole you can feel the tube...... I don't think this was a Bruce King design feature. Drill halfway through a cross member so it can introduce water into the grid?......

It's always difficult to compare boats. After 30 some years, it's always hard to know what was a factory install and what as an owner-mod somewhere along the way. Thought I'd it take a stab at some of your comments based on my differing experiences with my E32-3. YMMMV.

......As we know, boats with the TAFG, the grid structure introduced in the early 1980s, have a drip pan to isolate engine block spills. The molded-in pan sends such spills direct to the main bilge via a hefty tube that passes under the floors. I think on most boats, the idea was that the drip pan is truly "isolated," and does NOT flow into a main bilge section. Your picture shows the inlet tube for your whale gusher manual pump in this same compartment. Thus, this compartment needs to be connected via limber holes to the sub-TAFG and all other main bilge compartments if it is going to "de-water" the whole boat via the manual pump (and not just that single bilge compartment). I would not want oil or antifreeze from the "engine pan" draining into this compartment (which, as we just said, should be connected to all other bilge compartments and the the hull area below the TAFG). Or else, an oil leak here spreads to all other bilge & under-TAFG sections, creates a real mess, and likely fouls some bilge pumps.

However, the stuffing box (or DSS) is aft of the drip pan. So where does stuffing box leakage go?........It goes into a limber hole drilled halfway through the after lip of the pan.......Such water then moves "sideways" inside the transverse pan dam until it can find a route to the bilge........Well, on my boat at least, it comes out "stuff box drain" in the photo above..... This path of stuffing box water is unrelated to the path of engine drip pan contents. That drain is below it, and if you put a finger in the "stuff box drain" hole you can feel the tube...... I don't think this was a Bruce King design feature. Drill halfway through a cross member so it can introduce water into the grid? I have no real problem with the term "stuffing box drain," but I think it's simpler than that: stuffing box (or DSS) leaks, or any number any leaks (aft dorades, stanchion posts, thru-hulls) may leak directly onto the interior hull, beneath the molded TAFG. Water from these leaks runs along the curved bottom of the hull and ultimately collects, undetected, below the TAFG, until it rises to a level where it flows into one or more of the molded compartments that we typically call the "bilge."

The actual bilge (the lowest part of the interior hull) is really the sub-TAFG area we can't see, and not the tidy, smoothly gel-coated compartments we commonly refer to as the "bilges." By design, all these areas had to be connected via cutouts, limber holes, etc, so a leak anywhere on the boat can collect to a "common" area and, thus, be de-watered by any bilge pump. The usual exceptions to this are 1) the shower bilge, and 2) the engine pan, for which it is likely desirable to be kept "isolated," for obvious reasons.

Common leak areas that go directly to the sub-TAFG, and not into the molded bilges:

Galley thru-hulls: Stern thru-hulls:

 

[Christian Williams]

(In response to Message #4. We typed simultaneously)

The TAFG of my 381 is sealed from the bilges, and isolated from it by design. The TAFG is fitted with drain plugs in case water gets "inside" it.



The TAFG of my 32-3 was also sealed. The molded bilge compartments, like the one in the picture, were connected by limber tubes intended to isolate the bilges from the interior TAFG structure. Those tubes fall out after 30 years. Also, owner revisions break the seal.

As I say, the TAFG has inherent drainage issues. The hull tab zones--small swimming pools that catch water--are often located under floorboards not designed to be removed.

Water is not supposed to get into the TAFG structure, which often retains sawdust from construction. But it does. Often the only way to get it out is with a hand pump.

 

[Christian Williams]

Ken,

Regarding the flow of a potential 8 quarts of oil from the engine to the main bilge--maybe that's why the former owner closed the bilge-end of the tube with caulking.

I'll recheck to make sure It does drain as I said. [It doesn't. See correction in Message #11.]

The molded bilges are for rainwater from the mast, a sea down the hatch, or spilled Coca-Cola. Any "real" leakage likely goes into, or under, the TAFG. This was not in the brochures.

 

[u079721]

Sure wish I had pictures, but the "sump" or "engine pan" under the engine on my 38 did not have any opening to the bilge or TAFG - which I always assumed was to keep oil and fuel leaks out of the bilge proper. There was a lip on the aft edge of the pan that separated the engine pan from an area further aft by the stuffing box that did have an opening, which was connected by a pipe that ran through the engine pan and came out in the main bilge. The pipe may have been well sealed at one point, but by the time I got the boat there was enough of a gap that I'm sure stuffing box water made its way into the TAFG. The only time I really noticed was when I tried to completely empty the bilge with a hand pump, only to have more water mysteriously appear from the TFAG limber holes.

 

[Kenneth K]

Christian,

I can see now why we were talking different languages: my bilges are configured very differently from yours. All my main bilges have large limber holes (and no "tubes") at the lowest point in the bilge. This makes my 3 main bilge sections and the sub-TAFG into one, continuous, common-collection-point at the bottom of the hull. There is no sense, in my case, to differentiate between "bilge" and "sub-TAFG," because it is all the same volume.



That's how my boat was configured when I bought it. I just assumed all other similar Ericsons would be built likewise. Apparently not.

This setup has its plusses and minuses: One negative is that any spill, be it a can of Coke or the half quart of West Systems 205 Hardened I spilled last year, is free to propagate to all the adjoining areas.

The plus side is that any bilge pump can de-water any leak, since all leaks wind up in the common-collection-point at the bottom of the boat.

If an owner wanted isolated or sealed bilges, perhaps Ericson accommodated their request. The main drawback, however, seeming to be that if a bilge is truly sealed off, its pump can't readily de-water any other areas of the boat. The common-collection-point for water then becomes the cabin sole, at which point the wooden bilge cover floats off, the isolated bilge begins to fill from above, and the pump in that compartment finally begins to de-water the rest of the boat.

All of which may be completely sufficient to keep the boat from sinking (albeit with the cabin sole submerged and the interior water level a few inches below the engine compartment).

I'm betting, however, that when a new customer was writing Ericson a $200k+ check (late-1980s dollars), Ericson was happy to oblige whatever bilge configuration the purchaser requested.

 

[u079721]

Christian,

I can see now why we were talking different languages: my bilges are configured very differently from yours. All my main bilges have large limber holes (and no "tubes") at the lowest point in the bilge. This makes my 3 main bilge sections and the sub-TAFG into one, continuous, common-collection-point at the bottom of the hull. There is no sense, in my case, to differentiate between "bilge" and "sub-TAFG," because it is all the same volume.

View attachment 32630

That's how my boat was configured when I bought it. I just assumed all other similar Ericsons would be built likewise. Apparently not.

This setup has its plusses and minuses: One negative is that any spill, be it a can of Coke or the half quart of West Systems 205 Hardened I spilled last year, is free to propagate to all the adjoining areas.

The plus side is that any bilge pump can de-water any leak, since all leaks wind up in the common-collection-point at the bottom of the boat.

If an owner wanted isolated or sealed bilges, perhaps Ericson accommodated their request. The main drawback, however, seeming to be that if a bilge is truly sealed off, its pump can't readily de-water any other areas of the boat. The common-collection-point for water then becomes the cabin sole, at which point the wooden bilge cover floats off, the isolated bilge begins to fill from above, and the pump in that compartment finally begins to de-water the rest of the boat.

All of which may be completely sufficient to keep the boat from sinking (albeit with the cabin sole submerged and the interior water level a few inches below the engine compartment).

I'm betting, however, that when a new customer was writing Ericson a $200k+ check (late-1980s dollars), Ericson was happy to oblige whatever bilge configuration the purchaser requested.

View attachment 32630

Egad - that is the cleanest and driest bilge I have ever seen!

 

[Christian Williams]

Now for corrections to my initial post after a more careful examination.

Ken and Steve are right--the engine drip pan is isolated and certainly does not empty into any bilge (as I had said incorrectly). Water introduced aft of the drip pan, say from a leaking stuffing box, passes through a pvc pipe under the engine and into the keel bilges.

A few more hours in the bilge today revealed my problem and confusion.

The drain tube that passes under the engine has to step down to get under the floorboards and progress through the TAGF baffles to reach the keel level. OK, simple enough.

I decided to test the route by pouring a can of Diet Coke into the aft collection point, and then ventured into the cabin to observe it come out into the molded bilge. Nothing came out. Well, maybe the boat was thirsty.

I crawled back into the engine bay and poured in another can. That didn't come out, either. Anywhere. I considered pouring in a can of beer, but thought better of it.

Probing the tube from both ends with a fish tape, I pretty quickly realized that the tube is broken. The step-downs require pvc elbows, probably 30 degrees, maybe 45 or even 90. They've come apart. The Diet Coke is now trapped in the TAFG. And it'll stay trapped until the motion of sailing eventually weeps it down to the keel, or until I remove the saloon floorboards and reconnect the tubes. No big deal.

(This seems to be an issue similar to what Steve found in Post #8: the pipe may have been well sealed at one point, but by the time I got the boat there was enough of a gap that I'm sure stuffing box water made its way into the TAFG. )

As concerns the Ericson plan for drainage of the TAFG, Ken may be right that it was an owner option. But I now believe my boat was designed to drain the TAFG into the molded bilges. Sort of.

I have low, molded-bilge TAFG drain holes closed with screw-in plugs. I unscrewed mine and the bilge filled with cruddy water from the grid structure. However, I noticed for the first time that each compartment also has a side drain. All such side drains were sealed and painted. I opened one up--the silicone plug is shown in the photo. The side drains are apparently there to empty water caught in the hull, from, say, deck leakage.

Who sealed all of mine? Maybe the factory. Maybe a former owner.

...

Just to complicate matters, I have in some compartments higher holes in the athwartships grid walls, apparently to provide drainage there. That's where the Diet Cokes will eventually come out. That's where the red diesel fuel came out when I had a minor fuel-tank leak caused by a loose sender port.

So in the end, the TAFG on my boat is both sealed and not sealed, in the way a platypus is both a mammal and not a mammal.

Everything is so clear now, I am sure we agree.

 

[Frank Langer]

Now for corrections to my initial post after a more careful examination.

Ken and Steve are right--the engine drip pan is isolated and certainly does not empty into any bilge (as I had said incorrectly). Water introduced aft of the drip pan, say from a leaking stuffing box, passes through a pvc pipe under the engine and into the keel bilges.

A few more hours in the bilge today revealed my problem and confusion.

The drain tube that passes under the engine has to step down to get under the floorboards and progress through the TAGF baffles to reach the keel level. OK, simple enough.

I decided to test the route by pouring a can of Diet Coke into the aft collection point, and then ventured into the cabin to observe it come out into the molded bilge. Nothing came out. Well, maybe the boat was thirsty.

I crawled back into the engine bay and poured in another can. That didn't come out, either. Anywhere. I considered pouring in a can of beer, but thought better of it.

Probing the tube from both ends with a fish tape, I pretty quickly realized that the tube is broken. The step-downs require pvc elbows, probably 30 degrees, maybe 45 or even 90. They've come apart. The Diet Coke is now trapped in the TAGF. And it'll stay trapped until the motion of sailing eventually weeps it down to the keel, or until I remove the saloon floorboards and reconnect the tubes. No big deal.

As concerns the Ericson plan for drainage of the TAGF, Ken may be right that it was an owner option. But I now believe my boat was designed to drain the TAFG into the molded bilges. Sort of.

I have low, molded-bilge TAFG drain holes closed with screw-in plugs. I unscrewed mine and the bilge filled with cruddy water from the grid structure. However, I noticed for the first time that each compartment also has a side drain. All such side drains were sealed and painted. I opened one up--the silicone plug is shown in the photo. The side drains are apparently there to empty water caught in the hull, from, say, deck leakage.

Who sealed all of mine? Maybe the factory. Maybe a former owner.

View attachment 32633...View attachment 32634

Just to complicate matters, I have in some compartments higher holes in the athwartships grid walls, apparently to provide drainage there. That's where the Diet Cokes will eventually come out. That's where the red diesel fuel came out when I had a minor fuel-tank leak caused by a loose sender port.

So in the end, the TAFG on my boat is both sealed and not sealed, in the way a platypus is both a mammal and not a mammal.

Everything is so clear now, I am sure we agree.

Christian, while I applaud your scientific approach to problem solving, I can't agree with your use of beer. I might have tried water with food colouring in it to track water flow in the boat. Diet coke, well maybe... beer, no way, serious fault!
Frank

 

[Kenneth K]

"Everything is so clear now, I am sure we agree."

Well, mostly. Actually, I only got as far as, "I considered pouring in a can of beer, but thought better of it," and I stopped. Realizing at this point that both your reasoning and your method were sound and inarguably correct, I decided to leave well enough alone.

What more could possibly be said about the Ericson bilges at this point than what has already been discussed?

 

[nquigley]

Christian,
I can see now why we were talking different languages: my bilges are configured very differently from yours. All my main bilges have large limber holes (and no "tubes") at the lowest point in the bilge. This makes my 3 main bilge sections and the sub-TAFG into one, continuous, common-collection-point at the bottom of the hull. There is no sense, in my case, to differentiate between "bilge" and "sub-TAFG," because it is all the same volume.
View attachment 32630
That's how my boat was configured when I bought it. I just assumed all other similar Ericsons would be built likewise. Apparently not.

I have the same limber holes in my cabin sole bilge compartments as Ken (our hull numbers are close). Sticking a finger in them, one can feel the rough surface of the inside of the hull. I'm just hoping there are enough lateral limber holes to bring under-TAFG water down to where the bilge pumps are. I also have a completely isolated under-engine section - it's currently collecting coolant at a slow rate (I guess I'm about to learn all about that system now).
Eventually I'll replace my cabin sole - it'll be hard to resist the urge to add lots of extra lift-up flooring sections, so I can mop out any of the isolated swimming pools CW mentioned.

 

[Tin Kicker]

Not having the fuel tank in the boat gave an opportunity to take a couple of photos to share how much space there is beneath at least part of the TAFG. This is from the fuel tank bay looking forward in the 32-3:

Closer view:

In terms of volume, the space between the hull and TAFG liner could hold a LOT of water.

 

[Kenneth K]

I just took that same photo on my boat a few days ago. Having the tank out is allowing me to reroute and secure the battery cables in that area. The positive cable for my starting battery was draped OVER the top top corner of the fuel tank (over the fuel sender port). I just drilled a new hole on Saturday, to re-rerun the cable out the side of the engine compartment like yours are.

 

[Tin Kicker]

Found that the leaks in my tank were fatigue cracks along the edge of the baffle. Details here: https://ericsonyachts.org/ie/threads/cleaning-a-fuel-tank.17309/#post-127702

 

[nquigley]

Not having the fuel tank in the boat gave an opportunity to take a couple of photos to share how much space there is beneath at least part of the TAFG. This is from the fuel tank bay looking forward in the 32-3:

Closer view:

And from removing the through hull for the head, here's the space in that area:

Your pics bring back recent fond memories from when I removed my tank in January. Except ... my plywood piece under the battery box was completely rotted away - I slapped a layer of glass cloth up under there in it's place - and my power cables don't come in that way. On my boat, they all (ALL!) come in through an overlapped pair ~1.5" holes in the engine side wall right where your yellow regulator wire comes through. In addition to the power cables (with no chafe guard), that hole ported the small wires for the fuel pickup pump and the fuel out and return tubing - it was tight! I carefully widened those holes (without cutting the cables) and added chafe guard under the power cables. I do not have power cable holes where you do.
Your pics nicely show the nasty dark corner where I found a puddle of fuel and asphalenes and ?? - right where the corner of my tank corroded away. That corner is filled with a layer of fiberglass in my boat, making a pocket for leaked fuel to gather. It holds about a cup of liquid, and then it overflows around that corner of the cabin sole and onwards, forward, into the gap between the TAFG and the hull. I probably poured ~5 gal of Pine-sol type degreaser in that area (and used a long-handled scrub brush to get as far back there as I can) to chase years of diesel seepage along whatever paths it's taken. I wonder why they left that gap in your hull and sealed mine with a layer of cloth ??
Seems like the factory guys re-invented the wheel in this general area a couple ways over time.

 

[Alan Gomes]

(Might want to correct "TAGF" to "TAFG" in this thread's title so it doesn't cause problems for future title-only searches.)

 

[Christian Williams]

Thanks, done.