Ericson's ventilation systems

[Kenneth K]

Lately, Ive been scratching my head over Ericson's Dorade/Cowl vent system.

On the 32-3, there is a single dorade in front of the mast and two cowl vents at the stern. I think all are 3" diameter vents. However, when the boat is closed up, there are no vents or open air passages between the cabin (vented by the dorade) and the engine compartment (vented by the cowls).

Sure, while air can leak through cracks around cabinetry and doors/panels, a passive ventilation system needs easy passages for airflow (I would think an opening with at least the same area as a 3" dia. vent). It seems the only way to provide this in the 32-3 is to leave the under-sink cabinet door or the port-side engine access panel open. Otherwise, I don't see how passive ventilation is provided between the dorade and the cowls.

 

[Loren Beach]

Since there are no designed-in dorade's on the Olson's, we do keep both the foreward and house top hatches on the locked 'vent' position all year unless there is a storm forecast. I added two Beckson vents to the aft cabin top, many years ago, too. We have the usual two 3" vents on the top of the transom area, but I am not sure that they benefit the interior at all.

 

[Prairie Schooner]

Ken, your assessment seems about right to me. I've been pleasantly surprised by how much air flow comes in the forward cowl scoops via the dorade. We're on a mooring which helps with wind direction. As far as ventilation out, I haven't had time to really ponder.

On the E35-3 there is a 3" deck plate just about where the port aft life line gate stanchion is. This leads to a sort of internal dorade box next to the nav desk, with a drain to a thru-hull somewhere. There is a sign recommending the valve be closed when sailing. Our PO just had the deck plate filled with a screw on cap. We purchased a solar vent to put in there, but it's not a direct fit and I haven't got around to making an adapter yet.

 

[Bolo]

Lately, Ive been scratching my head over Ericson's Dorade/Cowl vent system.

On the 32-3, there is a single dorade in front of the mast and two cowl vents at the stern. I think all are 3" diameter vents. However, when the boat is closed up, there are no vents or open air passages between the cabin (vented by the dorade) and the engine compartment (vented by the cowls).

Sure, while air can leak through cracks around cabinetry and doors/panels, a passive ventilation system needs easy passages for airflow (I would think an opening with at least the same area as a 3" dia. vent). It seems the only way to provide this in the 32-3 is to leave the under-sink cabinet door or the port-side engine access panel open. Otherwise, I don't see how passive ventilation is provided between the dorade and the cowls.

Owner of a 32-3 myself I too have two cowl vents at the taffrail which, as Loren stated, don't benefit the interior at all and I doubt if they were ever meant for that purpose. My boat still has a exhaust fan attached to one of those cowls which I do turn on when running the engine for an extended period that does help with removing engine heat (what's a little more noise then anyway) and I was ever thinking of rewiring it so the switch on the engine control panel could be turned on even with the ignition switch off to suck hot air out of the engine compartment for a long period at the dock but I'm getting a bit off topic here.

I installed a solar powered vent in the middle of the center hatch, behind the mast, which does a good job of keeping a good air flow through the boat when it's closed and locked up in the hotter months. Plus, when I do leave the boat for an extended period of time I open the cabinet door under the galley sink, the cabinet door in the head, the door to the head and sometimes I even pull the bilge covers off to evaporate any little of bit of water that might find it's way into the bilge but not deep enough to set off the bilge pump. I do have a leak someplace that I'm trying to find that sometimes puts water in the bilge but not each time it rains only sometimes so it's been hard to track down. I also open the port in the head, which has a bug screen in it and a smoked plastic rain shield on the outside cabin wall (see the photo) which gives me even more ventilation. It's very rare to have rain get in through that port unless it's coming down so hard it bounces off the side deck and any moisture that might come in falls on the head counter top or plastic floor which is not a problem. With all I do I never have that "boat smell" that I use to have before adding the hatch vent.

 

[Loren Beach]

Having air move thru the boat and hopefully find it's way out is important.
Our boat has benefited from having a way to hold the doors open without them banging back no forth.

O34 - Vent Method for Cabin Doors

After accidently discovering that not all the early Olsons have the same "ventilation feature" as ours, I thought it might be good to try and share this feature. It's been copied by other boaters for other makes of boat around our YC over the...

ericsonyachts.org

The boat came with this feature.

 

[Kenneth K]

Thanks for the comments.

I guess I had always thought of the system as "air goes into the dorade and out the cowls." But, obviously, the mfg's general idea is largely to keep the engine compartment ventilation separate from that of the engine room--for good reason, at least while the engine is running.

Still, for the 95% of the time that the boat is sitting empty and closed up, it seems the cabin side of the system should have an "exhaust" vent of it's own. Those who've added solar vents or leave ports open have accomplished just that.

Maybe something I should consider.

 

[Bolo]

Thanks for the comments.

I guess I had always thought of the system as "air goes into the dorade and out the cowls." But, obviously, the mfg's general idea is largely to keep the engine compartment ventilation separate from that of the engine room--for good reason, at least while the engine is running.

Still, for the 95% of the time that the boat is sitting empty and closed up, it seems the cabin side of the system should have an "exhaust" vent of it's own. Those who've added solar vents or leave ports open have accomplished just that.

Maybe something I should consider.

Next time I’m on the boat I’ll take some photos of the solar vent install and give the brand name and model. Maybe even do a video short and put it on my YouTube channel.

 

[jtsai]

Good point about leaving cabinet door open to the engine to take advantage of cross circulation between dorado and cowls. I will start doing that when boat is at slip.

The dorado on my boat has two ports in the cabin, one is in the head, the second one is in the main saloon in front of the mast. Is this common in 32-3 or just mine? Does this introduce any cross ventilation?

 

[Kenneth K]

The dorado on my boat has two ports in the cabin, one is in the head, the second one is in the main saloon in front of the mast. Is this common in 32-3 or just mine? Does this introduce any cross ventilation?

I have the underside (under the headliner) of my dorade exposed presently because I'm managing some leaks. Air that enters the exterior scoop enters a rectangular housing connected to the two ports you mention (one in the head, one in the saloon). I don't think there's any cross- ventilation between those two ports.

 

[Parrothead]

Lately, Ive been scratching my head over Ericson's Dorade/Cowl vent system.

On the 32-3, there is a single dorade in front of the mast and two cowl vents at the stern. I think all are 3" diameter vents. However, when the boat is closed up, there are no vents or open air passages between the cabin (vented by the dorade) and the engine compartment (vented by the cowls).

Sure, while air can leak through cracks around cabinetry and doors/panels, a passive ventilation system needs easy passages for airflow (I would think an opening with at least the same area as a 3" dia. vent). It seems the only way to provide this in the 32-3 is to leave the under-sink cabinet door or the port-side engine access panel open. Otherwise, I don't see how passive ventilation is provided between the dorade and the cowls.

The stern cowls were never intended to contribute to passive interior ventilation, propulsion spaces only.

 

[LameBMX]

Don't know if it applies, but my companionway hatch does slide past the slats enough to create an opening. I could see that being close to the same area as a 3" cowl.

 

[bigd14]

The stern cowls were never intended to contribute to passive interior ventilation, propulsion spaces only.

My low profile PVC/vinyl cowl vents on the taffrail are decaying. They admit water in the winter as rain and snow gets blown in or it trickles in through the flush mount caps if I remember to install them. They are beyond repair with crazing in the bases. I would like to replace them but I’m not sure if the original design is the best solution. Has anyone replaced the factory vents with other better options, maybe something lower profile like this? I don’t think they are needed for passive ventilation. Thanks.

Vetus Scirocco Shell Vent - SCIROCCO

The Vetus Scirocco Shell Ventilator is made of stainless steel and can be screwed directly on to a hull or superstructure. Features: Includes a plastic base plate complete with water guard and 3" hose connection Can be mounted either horizontally

defender.com

 

[bgary]

leaving cabinet door open to the engine to take advantage of cross circulation

Late to the thread, but... I don't actually think the dorade does a whole lot. Big opening on deck, but by the time air makes its way through the dorade box and through that little hole in the overhead in front of the mast, I don't think there's a lot of flow. I've thought about replacing the dorade hood with a solar-powered fan/vent, just to "encourage" some air movement, but haven't yet. It's on the project list... somewhere.

In the meantime, when I close the boat up for the winter I put a fan all the way forward in the v-berth, and leave the cupboard door under the sink open. I also position the cowls on the taffrail so they face aft, thinking the prevailing westerly at my slip will suck some air out of the boat. If I hold my hand over one of the cowls I can almost imagine I feel a little flow. Either way, just having air circulating inside the boat seems to help.

Oh, and I run a couple of dehumidifiers and hang a couple of damp-rid bags, too, which (in combination with airflow) has just about eliminated mildew and mustiness over the winter.

 

[Bolo]

I agree about the dorado just forward of the mast. Even under way I never felt air coming through it. ( Maybe it’s clogged?) But I do have a solar vent in the big cabin hatch behind the mast that does a good job (I mentioned this early in this thread) and with my boat wintering in the water with access to shore power I‘ve used a West Marine dehumidifier for years and it too works well.

Air Dryer with Fan, Dehumidifier, 120V AC | West Marine

Check out our Air Dryer with Fan, Dehumidifier, 120V AC and more from West Marine!

www.westmarine.com

 

[frick]

Owner of a 32-3 myself I too have two cowl vents at the taffrail which, as Loren stated, don't benefit the interior at all and I doubt if they were ever meant for that purpose. My boat still has a exhaust fan attached to one of those cowls which I do turn on when running the engine for an extended period that does help with removing engine heat (what's a little more noise then anyway) and I was ever thinking of rewiring it so the switch on the engine control panel could be turned on even with the ignition switch off to suck hot air out of the engine compartment for a long period at the dock but I'm getting a bit off topic here.

I installed a solar powered vent in the middle of the center hatch, behind the mast, which does a good job of keeping a good air flow through the boat when it's closed and locked up in the hotter months. Plus, when I do leave the boat for an extended period of time I open the cabinet door under the galley sink, the cabinet door in the head, the door to the head and sometimes I even pull the bilge covers off to evaporate any little of bit of water that might find it's way into the bilge but not deep enough to set off the bilge pump. I do have a leak someplace that I'm trying to find that sometimes puts water in the bilge but not each time it rains only sometimes so it's been hard to track down. I also open the port in the head, which has a bug screen in it and a smoked plastic rain shield on the outside cabin wall (see the photo) which gives me even more ventilation. It's very rare to have rain get in through that port unless it's coming down so hard it bounces off the side deck and any moisture that might come in falls on the head counter top or plastic floor which is not a problem. With all I do I never have that "boat smell" that I use to have before adding the hatch vent.

View attachment 44244

My old e29 has drier hoses from those after funnels to the engine box

 

[Christian Williams]

The twin dorade cowls on the foredeck of the E381 make a real wind inside the boat, essential to comfort offshore when all hatches are closed. When it's cold, I have stuck a sock in them.

There is no air exit path, as the engine bay and aft cabin are sealed.

Dunno why, but the dorades are remarkably effective on this model.

 

[Loren Beach]

We routinely keep both of our Lewmar hatches on their locked "vent" positions. We have two Beckon SS vents aft, one over the head compartment and the other over the aft cabin. This has worked very well for many years. Those Beckon vents really work; you can put your hand up under either one when there is any breeze over the deck at all and feel the updraft.

 

[bsangs]

The twin dorade cowls on the foredeck of the E381 make a real wind inside the boat, essential to comfort offshore when all hatches are closed. When it's cold, I have stuck a sock in them. Dunno why, but the dorades are remarkably effective on this model.

Ditto on the 35-3. Lot of air comes through those front dorade cowls. I leave the engine door off, and keep the galley sink cabinet door open all winter - and sometimes during the summer - and, like Loren, leave the Lewmar hatches in the vent positions when possible. Seems to provide adequate ventilation when the boat is closed.

 

[Christian Williams]

On topic of ventilation, the former owner installed a big cowl in the coaming for engine ventilation. It works very well with the two fantail cowls, which I increased in size (stainless models). He also had an elaborate system of air exchange ducting, with multiple in-line fans in 20' of 4" vent hose.

That made a jungle of hanging hoses which restricted access under the cockpit. I ripped it all out and have relied successfully on passive venting since.

 

[Prairie Schooner]

Ditto on the 35-3. Lot of air comes through those front dorade cowls. . . .

+1 _ Perhaps this is because the 35s and 38s have two cowl vents on the dorade.