Catamaran Ventilation Solutions?

[Chotu]

One thing I never see on cats is dorades.

How are your hulls ventilated?

How do you get a continuous supply of fresh air to the forward staterooms down in the hulls when it’s pouring, blowing rain?

[atoll]

Originally Posted by Chotu

One thing I never see on cats is dorades.

How are your hulls ventilated?

How do you get a continuous supply of fresh air to the forward staterooms down in the hulls when it’s pouring, blowing rain?

i can leave my self draining forward facing anchor locker lid open as a wind scoop.
a hatch in the locker to the saloon and vents to each hull provide a constant airflow through the boat,any rain just drains out the bottom of the anchor locker

[Tupaia]

My escape hatches are forward and can be left open at anchor rain or shine.

[ggray]

Yes, that can be a bit of a problem, with unique (partial perhaps) solutions to each boat.

I can get fairly good ventilation in the main cabin, and much better with the "escape hatch" open while at anchor. Could use fans to move air to forward cabins

The solution, which I have not implemented, would be to install a deck plate on the face of a locker in the bridge deck and open or duct that to the forward cabins. Would likely need to screw in the plate in really rough conditions. Maybe have multiple small deck plates or even use hose fill fittings

And you need to provide a way for the air out if the companionway is secured.

But I'm all ears for any other solutions!

[chrisr]

no denying ventilation on our boat is difficult when it's heavy rain. deck hatches (all 6 of them) and side windows (another 6) need to stay closed. light rain most can stay open a crack

however this never seems to become a problem...i think partly because the spaces / cabins are quite large and partly because the large doors / windows that open on to the cockpit are under the roof, and can stay open even in heavy rain. not strictly speaking getting'through flow' but but there is enough air volume and plenty of fans

worse case...start the air con

cheers,

[smj]

We have 2 queen sized bunks, both on the bridgedeck. Like Atoll each bunk has 2 hatches that open to the forward lockers so we can leave the hatches open in the rain. On the aft side of the bunk is a large hatch that opens directly to the cockpit which also doesn’t leak while open so great cross through ventilation on the bunks even while raining.
Ventilation to us is an extremely important attribute to look at while deciding on a boat.

[Chotu]

Hmmm. The opening hatches into deck lockers is not ideal for me. Deck lockers are invariably moldy and foul. I can’t be breathing that.

Maybe I can add a couple custom, ultra low profile dorades, using the forward beam’s shroud as the box and air conduit. You know.. that area where the bridge deck gets all aerodynamic before the trampoline begins?

Inside that curve is basically unused space in my boat so far. Just for some storage, which it could still do if I set up airflow through it.

[smj]

Originally Posted by Chotu

Hmmm. The opening hatches into deck lockers is not ideal for me. Deck lockers are invariably moldy and foul. I can’t be breathing that.

Maybe I can add a couple custom, ultra low profile dorades, using the forward beam’s shroud as the box and air conduit. You know.. that area where the bridge deck gets all aerodynamic before the trampoline begins?

Inside that curve is basically unused space in my boat so far. Just for some storage, which it could still do if I set up airflow through it.

We’ve yet to notice anything moldy or foul coming from our forward lockers, could be the great ventilation they receive!

[Sparx]

Opening portlights on the inboard side of each hull provide fantastic ventilation to the forward spaces. The wind seems to channel in between the hulls allowing the portlights to provide very satisfying flow when at anchor. The portlights are located just below the trampoline.

The overhead hatches channel hot air off the deck into the interior. The portlights channel the cooler air from just above the water into the boat.

[Chotu]

Originally Posted by smj

We’ve yet to notice anything moldy or foul coming from our forward lockers, could be the great ventilation they receive!

I don’t doubt that.

I have severe allergic asthma triggered by mold. Our mold tolerance scales are different.

Running rigging out all day long in the fresh air is moldy. In fact, nearly every boat in existence is moldy (on my tolerance scale of “this is uncomfortable” to “I can no longer breathe “)

The purpose of the fresh air draw I need is to blow any mold spores from the interior out of the boat. Even ones no one else could notice.

The boat is all white inside and scrubbable with no hidden spots.

A fan and whole house HEPA filter on these fresh air draws may also be fitted so I can pull in cool, fresh air when my other trigger (particulate pollution) is high.

It’s a cool idea, but it can’t work for me because whatever I put in the locker will get moldy.

And come to think of it, all I have is a monster size anchor locker forward on the bridge deck that holds all the ground tackle, fenders, extra lines, etc

[Chotu]

Originally Posted by Sparx

Opening portlights on the inboard side of each hull provide fantastic ventilation to the forward spaces. The wind seems to channel in between the hulls allowing the portlights to provide very satisfying flow when at anchor. The portlights are located just below the trampoline.

The overhead hatches channel hot air off the deck into the interior. The portlights channel the cooler air from just above the water into the boat.

Hmmm. This might be workable. I definitely know what you mean about the wind getting squeezed between the hulls and creating a natural higher pressure area.

No hepa filters but workable. Any good in a blowing 30 knot rain?

[Sand crab]

This company makes porthole covers. I saw a similar product for hatches somewhere.
Rain shields for portholes & engine panels ~ Seaworthy Goods

[smj]

Originally Posted by Chotu

I don’t doubt that.

I have severe allergic asthma triggered by mold. Our mold tolerance scales are different.

Running rigging out all day long in the fresh air is moldy. In fact, nearly every boat in existence is moldy (on my tolerance scale of “this is uncomfortable” to “I can no longer breathe “)

The purpose of the fresh air draw I need is to blow any mold spores from the interior out of the boat. Even ones no one else could notice.

The boat is all white inside and scrubbable with no hidden spots.

A fan and whole house HEPA filter on these fresh air draws may also be fitted so I can pull in cool, fresh air when my other trigger (particulate pollution) is high.

It’s a cool idea, but it can’t work for me because whatever I put in the locker will get moldy.

And come to think of it, all I have is a monster size anchor locker forward on the bridge deck that holds all the ground tackle, fenders, extra lines, etc

Yes you are right, I do have some asthma problems with mold but I’m guessing nowhere as serious as yours. I also wonder if dorados would build up mold over time?
A neat setup was done by the previous owner of the Crowther Spindrift Zingaro. He drilled 4” holes in the forward underside of the bridgedeck, 2 per side. He then added a cap on top. Caps were on while sailing and of at anchor allowing some good ventilation. Probably wouldn’t be to hard to make a cap with bug screen as well.

[smj]

Originally Posted by Chotu

Hmmm. This might be workable. I definitely know what you mean about the wind getting squeezed between the hulls and creating a natural higher pressure area.



No hepa filters but workable. Any good in a blowing 30 knot rain?

We have a port on the inside of the hull on our Searunner. Nice ventilation but it does let the rain in.
All the ports on the Searunner open and my wife made some air scoops out of some plastic trash cans from the dollar store. They work well but don’t keep the rain out!

[Chotu]

Originally Posted by smj

Yes you are right, I do have some asthma problems with mold but I’m guessing nowhere as serious as yours. I also wonder if dorados would build up mold over time?
A neat setup was done by the previous owner of the Crowther Spindrift Zingaro. He drilled 4” holes in the forward underside of the bridgedeck, 2 per side. He then added a cap on top. Caps were on while sailing and of at anchor allowing some good ventilation. Probably wouldn’t be to hard to make a cap with bug screen as well.
Attachment 219139

Brilliant!!

This is one of those “why didn’t I think of that” moments.

Here I am thinking of complex monohull solutions like dorades boxes when a catamaran solution makes way more sense.


I could put these in my forward shroud very easily for awesome ventilation.

Thank for this idea. It makes the most sense of all of them actually. Simple to fit a screen in them for bugs, rain can’t get in, cap them for offshore.

Perfect!