Ventilation in Aft Cabins/Center Cockpit

[Hydra]

A partial cure for waves slapping under the stern is pushing 2 big fenders there. On my boat, I tie these 2 fenders together and set one on each side of the rudder, with a line made fast on the deck to keep them in place. It is effective enough to make sleep possible.

Alain

[capta]

Originally Posted by CarlF

I've always been comfortable in an aft cabin as long as it had a place for the air to exit. Any opening near the transom will tend to pull the air through the cabin. Still air is miserable.

If you have dorades in the aft cabin, I'd turn them facing aft. You could even mount them over the lazarette and use hose to bring the air from the cabin.

Portlights (especially big portlights) in the transom are wonderful. You do have to close them underway but at anchor it's great.

Dorades will not exhaust air. Open one and look; no direct connection between funnel and through deck tube.
As mentioned above, wind scoops won't work w/o an air exit.

[Cptn Happy]

My wife and I cruised the Bahamas/Caribbean for a year and half on our 40" Endeavour centercockpit. It has three opening ports in the aft cabin, plus one in the adjoining head. A hella fan was mounted on a bulkhead near the foot of the bearth. What REALLY made the difference was an overhead hatch w/ a windscoop attached. The bimini did not block the wind but the dodger would have if we had kept it up(which we rarely did). Admittedly, there were a few night that we would have liked ac but when you live w/out it for awhile you acclimate. Bottom line, you won't get much benefit from a windscoop behind a dodger.

[Pelagic]

As others said, the key is to have an exit for the hot air.

In our aft cabin, we don’t have deck hatches or dorades, as it is aft cockpit.

However, we can create a great flow thru whole yacht by opening the forward deck hatches and the hot air will exit aft cabin via an inside door access to the aft Storage Locker.
When we open up that door plus locker’s deck hatch, it creates a real chimney/ or air flow venturi effect, (not sure which).

This way, we don’t need to open up our port lights and works well to keep the cabin cooler in the Tropics.

[daddle]

Install a deck hatch. Anchor by the stern. Maybe.

(Doesn't work well underway)

[GaryMayo]

Windows to the aft cabin, do not need to be only outside your sailboat. This is an example of ventilation from inside the cockpit that would also let in sunlight. Like another hatch, but not underfoot.

I will be adding a couple of these if ventilation turns out to be a problem.

Picture from another thread in this forum, same subject

http://www.cruisersforum.com/forums/...ins-77275.html

[Dockhead]

Originally Posted by CarlF

I've always been comfortable in an aft cabin as long as it had a place for the air to exit. Any opening near the transom will tend to pull the air through the cabin. Still air is miserable.

If you have dorades in the aft cabin, I'd turn them facing aft. You could even mount them over the lazarette and use hose to bring the air from the cabin.

Portlights (especially big portlights) in the transom are wonderful. You do have to close them underway but at anchor it's great.

Cross-ventilation is kind of fundamental to life without air conditioning. I don't have transom ports in my boat (there's another six feet of boat between my aft cabin and the transom), but I have ports on either side which create a good draft since my boat, like every other, never lies exactly head to the wind. If I really get desperate for more draft, I turn the dorades in opposite directions.

[nhschneider]

We've had our center-cockpit/aft-cabin ketch for 17 years now and much of our cruising is in the tropics. I recently replaced the fixed portlights with opening ones but other than that and the large escape hatch, our only source of air movement is two Hella 12v fans. While it's tolerable, it is pretty hot. A wind scoop would be very difficult to fit with the mizzen mast in the way and there's no good place to install dorades. I'm actually considering some sort of 12vdc air conditioning as we're heading to Indonesia.

Fair winds and calm seas.

[forsailbyowner]

I'd recommend a large scoop over the bow and a way for air to exit the stern. If you have a canvas closure to cover the companionway it will direct the air to exit aft. Also a shade cover for the stern. Keeping the sun off the deck over head makes a world of difference.

[gettinthere]

We have an Endeavour 42 CC. Prior owner changed the fixed ports in the stern of the aft cabin to opening ports. We put up wind scoops, etc but it's still hot back there till we open the aft ports. Then the flow is excellent.
The very large overhead hatch doesn't do much even when the bimini is wide open, windows rolled up.

[Tortuga's Lie]

I suspect that in many aft cabins, the ensuite head would stop any sort of through-boat air movement and the passageway becomes the funnel for the air. The problem is that many times this passageway is not in direct line with the berth. Has anyone cut an opening through the bulkhead in the head to create a passageway for the airflow? I would imagine that many times, this bulkhead would be directly aft of the galley. You could hinge a door of sorts that you could close off for privacy and open for ventilation???? Thoughts?

[The Boat Galley]

A four-way wind scoop will funnel a lot of air -- I like them better than a regular one as you don't have to reposition it every time the boat moves. You can either use it on a hatch in that aft cabin, or just open all the ports and hatches in the aft cabin and use it on a different hatch -- close the companionway and other hatches and that air will be directed through the aft cabin on its way out.

A great source for 4-way (omnidirectional) wind scoops is Cruising Solutions (less than half the price that others sell them for, same quality):

Breeze Bandit from Cruising Solutions

I also like the Caframo fans -- the ones without a cage (they're still finger safe) -- they move a lot of air for the amps used.

[Cheechako]

Originally Posted by Tortuga's Lie

I suspect that in many aft cabins, the ensuite head would stop any sort of through-boat air movement and the passageway becomes the funnel for the air. The problem is that many times this passageway is not in direct line with the berth. Has anyone cut an opening through the bulkhead in the head to create a passageway for the airflow? I would imagine that many times, this bulkhead would be directly aft of the galley. You could hinge a door of sorts that you could close off for privacy and open for ventilation???? Thoughts?

I dont know about the head, but the engine room is usually in the way. Air should flow from the front down the passageway (assuming not a walkover), but the for it to flw is needs an escape inthe rear..

[GaryMayo]

My engine room is in the middle of our sailboat, under the cockpit. Buttoned up pretty tight from the two sides. Each side has a separate compainonway. Openings on all four sides as well as the top.

[Doodles]

Hi Tom,

Have you talked to Steve Thompson on C-Dock? He's got the Gulfstar 50 (end of the dock) which is a center cockpit. I'm in Thailand right now but I'm pretty sure its got opening side ports and a big overhead hatch. You might check with him on what his ventilation is like and the aft head setup.

Danny (aka Doodles)
s/v "Whisper"

P.S. Say hello to Barbara for us and I hope you guys have a great holiday.