Ventilation in Aft Cabins/Center Cockpit

[Tortuga's Lie]

All,
I have an aft cockpit sloop and primarily sleep in the V- berth where we have excellent ventilation while on the hook. I am thinking of up sizing to a mid 40's center cockpit. So, my question is this......I could imagine that the natural ventilation of the aft cabin is severely limited so what do you do to supplement the airflow effectively? I do not want to rely on a generator just to run an air conditioner.
Thoughts/ experiences???

Thanks,
Tom

[Stu Jackson]

Dorades, opening ports and fans.

[Tortuga's Lie]

Originally Posted by Stu Jackson

Dorades, opening ports and fans.

Well, yes those would be obvious but how effective would a dorade be sitting behind the center cockpit coaming and/or full enclosure?

How effective are windscoops?
Can you funnel air through the boat more effectively?
Is the luxury of the aft stateroom worth the penalty of ventilation?

[Dockhead]

I've got two big swivelling dorades (which I can aim into the wind to increase the air flow) ventilating my aft master cabin, plus opening side ports giving cross-ventilation, plus a large opening overhead hatch.

I might not be the most demanding judge of ventilation, since I sail in a cool climate, but this seems pretty good to me.

Dorades are good if they are big enough. I have six big ones on my boat; wish I had three more (one each for forward heads, forward pullman cabin, aft heads).

[Kenomac]

Our current center cockpit has two dorade vents, one large opening hatch with a screen and two ports; plenty of ventilation. Even our Hunter 450 had four opening ports and a large hatch offering plenty of cross ventilation. You'll find most center cockpits equipped this way.

[Tortuga's Lie]

How about those windscoops specifically designed for portlights? I have seen these at boat shows in the past....anyone try these yet? I guess they would catch and funnel wind fairly effectively when pointed forward.

Any opinions for aft cabin ventilation in the tropics? How hot does it get in there? I guess a sun awning would make a big difference.

[capta]

We have some problem with the ventilation in our aft cabin. With a large hatch, 4 opening portholes and 2 dorades the aft section (aft of the hatch and ports) still has no airflow. Hot air just sits back there and the fans only circulate it, not exchange it.
I believe the only way to properly ventilate an aft cabin is to have an exit for air aft of the bed, like transom ports.
It's complicated for us as we have a lazarette aft and a locker above the bed so we will have to duct the air out. We're thinking of the solar exhaust vents to help.

[bstreep]

The big key to aft cabin ventilation is an exit for hot air out the stern. You can use windscoops to push air in, but unless it travels through the cabin and out the stern, you won't get good airflow. We have 2 portlights in the stern.

[Tortuga's Lie]

Thanks for the replys! Several of the aft cabins that I am looking at do not have portlights facing aft, either because of storage lockers directly behind the cabin or maybe because of deck space. If there is room and it makes sense, adding a portlight is easy enough. I chartered a boat in the BVI's that had aft-facing ports that needed to be closed during motoring or else exhaust would enter into the cabin...not a good thing. Of course, these ports were below the cap-rail level.
I suppose that if it gets too hot in the aft cabin, ther's always the V-berth to run to

[rebel heart]

My daughter sleeps in the quarter berth, aft cockpit boat. The biggest problem we have is running the engine in the tropics. No matter how much air you scoop through it gets friggin HOT.

Otherwise a blend of deck vents and fans. We have an AirOnly flush deck powered vent that exhausts air out, and a fan nearby that that blows in. The engine compartment also intakes air from there, so there's a decent amount of airflow.

[Cheechako]

Make sure you have a hatch overboard the cabin and use one of those big nylon hatch scoops. They work so well I often had to take mine down.... the breeze was so strong down below. There is a wooden flexible rod that slips through the hatch, no permanent holes to drill etc.

I've found dorades to be nearly useless for a cooling breeze. Good for just general boat ventilation though. I suppose they are a little better if not mounted on a proper dorade box and large. "Hey honey, did you see how far the mainsheet threw that dorade!" :>)

[Tortuga's Lie]

I regularly use a four-square windscoop on out Tartan for the V-berth and it works great, but wouldn't it get blocked by the dodger/bimini using it on an aft cabin? Maybe an extra tall one that funnels from above the bimini?

[Cheechako]

Ya, everything is blocked to some extent back there, but compared with say a dorade or portlite...... the big scoop should help alot.

[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.

[CarlF]

A bigger issue for me on some modern aft cabin boats is wave slap under a flat transom. The waves go under the transom and whack the fiberglass right under your pillow. It can seem like you are in an oil drum.