A25 under-engine limber holes

[WillieC]

Any of you out there with your engine currently removed?

I ask because apparently during rough seas, we take in a bit of seawater in the engine vent tubes on the rear deck. That water migrates toward the engine then seeps into the engine pan from the holes/not holes located on the sides of the engine drip pan. For this to happen, the level has to build up fairly substantially, or more likely, sloppy seas moves that accumulated seawater around down there.

The low point, at rest, in this whole maze of fiberglass appears to be at the stern end of the engine pan, right below the transmission coupler, under the notch for the driveshaft. Right behind this area is the deep groove, the bilge for the whole boat. This is where your sump pickup(s) are located and where the drainplug is also situated, down low on the port side.

It seems to me, that there ought to be a limber hole that drains that area under the engine pan into the deep bilge where it can actually be dealt with. This hole would be directly above the drain tube that runs from the front and under the engine pan. Right now, I have resorted to stuffing a highly absorbent towel into the notch between the two rectangular engine air holes, soaking it up, and wringing it our into a bucket. While this has a certain A25 slow vibe to it, I have better things to do with my spare time.

Am I missing a limber hole in the described location? I will continue to investigate all possible sources of water ingress to the breather tubes, but I am fairly certain it is the upper terminations at the rear deck. I installed new covers there this season, and they may not be up to the task of the crazy water we find ourselves in from time to time.

I am quite certain this water accumulation is not fresh water from an overflowing potable water tank. (That huge red cover with its immense o-ring really should be watertight, but isn't.) The forward bilge drain and its tube that runs under the engine pan is intact and unobstructed. Any accumulated water from the front of the boat makes its way unimpeded to the rear deep bilge area.

This winter I will be solving the missing limber tube(s) under the head sole as well. I may have plugged the starboard side when I glassed in new battery supports under the helm.
Sure glad this isn't a woodie.

Thanks for reading!

[ssrig]

From what I have seen there is not a drain from the engine pan to anywhere! Which would make sense as you want to contain the oil/coolant and whatever other toxic waste that oozes out the engine.
So the next thing to ask is what kind of weather are you out in??

I typically don't go out in bad weather, I'm retired and have lots of time so I wait until the conditions are good but I did do a run last year in big following seas with some large waves and nothing came close to entering the engine room vents, that would be some pretty wild waves! I feel like the water getting into the engine pan must come from another source, fresh water could enter the vents from rain or cleaning the deck with a hose, you may have a leak from your raw water system somewhere but I would be skeptical about sea water entering those vents on the rear deck.

[WillieC]

You are, correct, Yves, there is no drain from the engine pan to anywhere. Until it overflows...

The water is collecting in the air tubes, all of which is below the engine pan. If you have enough access, you can stick your hand between the two rectangular vent holes (if you can get under the exhaust recess cast into the glass). Right there is where the water seems to collect. I am 99% certain it is raw water, but then everything in that area tastes of salt, with a hint of Delo, followed by fine finish of dyed diesel. Slight overtones of decomposed tuna occasionally can be tasted on the back of the tongue if the sample was dipped from the bottom of the bilge.

I have checked the entire raw water system for leaks and come up with nothing, but again, any leaks therefrom would end up either in the bilge section beneath the exposed section of the driveshaft, or the engine pan.

The other possible point of ingress is straight through the hull or keel. I'll have to look more closely when it goes on the trailer later this week.

As to rough seas...come on dude! git out there! I agree, I don't CHOOSE to go out there, but sometimes it just happens. We ran into the wall of water at max ebb on Hood Canal yesterday. Fortunately very light wind. Quite the sight to see, though it is not at all massive, but certainly noticeable.

Maybe, maybe...the height of the air inlet in the new vent thangs is below the height of the rub rail which wouldn't take much of a deck slop to take on water. We got waked enough this trip which might have contributed. Somebody earlier here at AOG was pondering mounting the vent terminations on the vertical stern portion of the hull. I wonder how that is working out.

[DesertAlbin736]

Ives,

Congrats on retiring. Now you can cruise for as many consecutive day/weeks as you like & not have to worry about going back to work or paid vacation limitations. No need for long distance "DAing" since you're already close to the best cruising grounds anywhere.

Rick,

Ha ha, we know about rough water, Cattle Pass, Haro Strait, Straits of Georgia & Juan De Fuca, don't we? Seems like in his infinite wisdom Per Brohall would have built in some provisions to drain the engine vent system to the bilge outside of the engine compartment. Perhaps they exist but are just clogged up? The engine bed definitely should not drain to the bilge.

Our sailing friends on their aborted crossing of the Great Lakes had a fuel leak due to faulty O-ring on the secondary fuel filter & had 5 gallons of diesel overflow into the bilge & pumped overboard before they knew what was happening. They got pulled over by the Coast Guard & towed back to port & had to fix the problem, get inspected & cleared before they could continue on. Lucky for them they got off with a warning & didn't get cited or fined which would have be VERY expensive. That was just one of several headaches they had to deal with.

[DesertAlbin736]

PS, I'm not going to look in my boat today, supposed to hit 109 here today. Summer is a long way from over in these parts.

[WillieC]

"Seems like in his infinite wisdom Per Brohall would have built in some provisions to drain the engine vent system to the bilge outside of the engine compartment."

The perfect place to do just that is to drill a hole at the low point of the gathering pool in between and just aft of the two rectangular engine air holes. It would drain into the official bilge section just above the shaft. That is potentially sketchy, but the amount of water we are talking about is not much. Just don't drill through the hull.

My only concern is that I don't want the official bilge section to backwash into the air tubes via the new hole. That is easily fixed by a working bilge pump and periodic inspection. Since we do daily engine checks that much is easy. My next concern would be what could possibly go wrong with a new hole in the boat? You know, the whole unintended consequence issue.

Twelve hour nonstop run yesterday from Poulsbo to the mooring ball. The MD17C purred like a kitten. In a manner of speaking. And today is gorgeous on the Canal.

[DesertAlbin736]

"The MD17C purred like a kitten. In a manner of speaking. And today is gorgeous on the Canal."

Envy!

[nebulatech]

Rick, I'll take some photos of my air vents, but they don't match your description. I'm unfortunately taking care of my wife in the hospital, so I can't give you a timeframe. Below is the most relevant photo on my phone. FWIW, I'm considering getting one of those cameras at the end of a flexible rod, think endoscope, bore scope, etc., so I can investigate inside all of these drain tubes, bilges, vents. No plans to put a motor in any time soon, so I can hopefully provide some better data in the future.

20210820_123230.jpg

[WillieC]

Thank you! That is a perfect picture! This looks exactly like the WillieC. I apologize for my prior poorly over-worded descriptions. Even though the rectangular vent holes are obscured by the wood floor frame. Y'all know where those holes are.

Notice the angled ducts come in from the bottom of the picture and connect to the transverse section of fiberglass that has three notches: Left for raw water hose, center for propeller shaft, and right for exhaust hose. The ducts actually penetrate that structure then immediately open up into the rectangular holes that provide combustion and cooling air for the engine. The floor framework almost perfectly conceals those openings.

It is the point of where the triangle meets the hull, directly beneath the driveshaft where the water pools up...water I am assuming that enters the system from the rear deck vents, until convinced otherwise. When in motion, that pooled water sloshes forward and then if enough builds up, finds its way into the engine pan from the holes/not holes cast into the sides of the engine pan just behind the front engine mounts. Nebulatech's fine paint job and angle of picture pretty much obscures those holes/not holes. I, too, am considering a borescope of some kind.

I think a limber hole drilled right beneath the shaft and plugged with a cork or rubber stopper ought to serve as a drain for that area. The cork would remain in place in the event of a fuel leak hopefully to keep fuel out of the bilge section. Check often.

Which brings to question exactly how is the keel constructed? It appears to be solid both in front of and to the rear of the visible portion (from inside the boat), the deep section where fluid and excreta accumulate either to be pumped overboard or drained by removal of the plug. The rear portion of the keel contains the shaft log and so I presume it is solid, built up of a few buckets of glass and fiber. I am also assuming the portion forward of the "bilge" is also solid as it gently angles into the front vee of the hull. Anyone cut their A25 hull open, just out of curiosity? Gentle banging with a rubber hammer (boat on trailer) clearly indicates the hollow bilge section, where the drain plug is. The tube that drains the front section of hull, ahead of the engine disappears into solidity at the front and reappears in the bottom front of the bilge section. I assume it was bedded in the keel with another few buckets of resin and glass when layed.

Thanks for a great picture.

And thanks for taking care of your wife. There are things more important than boats.

[LydiaS]

#1729 is pretty much empty now, I hope these photos may help a bit.

[WillieC]

These are great photos as well! Pretty much confirms what I noticed earlier.

Thank you!

[Plum76]

So, the little ~2" plug at the aft end of the engine bilge (in the bottom) has started to flake out in my bilge, was planning on cleaning out and replacing with epoxy, any reason to do anything different? It appears to be a filler of some sort, not like fiberglass (no fibers in mine at least), and I suspect it's coming apart is the source of my trace of engine oil making it into the main bilge.

Any thoughts on that?

Plum

[WillieC]

My engine pan has no plug at the aft end. I used to think it odd until I realized the point of the engine pan is to catch and HOLD any engine fluid leaks, rather than letting it dump into the bilge.

The engine pan is not large enough to accommodate a Racor type fuel filter, so mine basically hangs above the port side rectangular breather hole. Any fuel leak would then dump into the breather tube (where my errant seawater also collects). This is why I am pondering drilling the limber hole described earlier AND fitting it with a plug of some kind. I want to know that only seawater is being dumped into the bilge from the breather tube.

If you are referring to the tube that dumps into what I am calling the bilge section, way down low, the deep section in the keel just under the exposed shaft, that is not an engine pan drain. That is the drain tube from the front boat section.

[Plum76]

I'm guessing the plug was a permanent fixture from new, just needs replacing. I don't think it is intended to drain anywhere, I think it's just a remnant from molding, perhaps a form release or a spot to check quality control from the original molds, then sealed on it's way out the door. I just need to replace the seal at this point..

I ended up putting my racor unit right by the diesel tank itself, and managed to cut my rubber fuel hose runs to about 1/4 of what they were originally, have not had any issues with that location, and it's certainly tidier than when I bought the boat. The old separator was in the engine bilge, port side in the aft, and was really crammed in there, no room to service and lots of extra hose to get it fed and back to the pump..

Jason

My engine pan has no plug at the aft end. I used to think it odd until I realized the point of the engine pan is to catch and HOLD any engine fluid leaks, rather than letting it dump into the bilge.

The engine pan is not large enough to accommodate a Racor type fuel filter, so mine basically hangs above the port side rectangular breather hole. Any fuel leak would then dump into the breather tube (where my errant seawater also collects). This is why I am pondering drilling the limber hole described earlier AND fitting it with a plug of some kind. I want to know that only seawater is being dumped into the bilge from the breather tube.

If you are referring to the tube that dumps into what I am calling the bilge section, way down low, the deep section in the keel just under the exposed shaft, that is not an engine pan drain. That is the drain tube from the front boat section.

[SalishAire]

Been wondering about this - Mind you my last boat was an offshore Nordhavn with many scuppers about 5 inches tall by 9 inches long and on many occasions the green water coming over the pilot house needed to escape through those holes. Sooooo Clarice and I keep feeling a bit wary about a boat with a center cockpit with no gravity exit for the water! Question, does the design of the boat keep the cockpit pretty dry in rough seas or are we highly dependent on bilge pumps????? (Yes we do tend to end up in rough seas at times despite being retired.)