Galley Ventilation

[mischief]

Hi I'm hoping someone out there may have gone through the same thing thing I'm working on.
I really want some good ventilation at the galley for when cooking not only on the hook but while cruising.
I've just installed an mushroom Air only ventilator. The type that has the balls in it so that it can take on Green water. (I've now 6 mushrooms and 4 cowl of these installed. (Oh crap my phone is acting up and I can't see what I'm typing ) please bear with me. )
Now I would like to add a fan to take the steam /cooking byproduct and guide it out the vent that is just a I've the stove. The vent has quite a few turns to exit plus it needs to go around the balls etc. I guess what I'm saying is the flow on the vent is not the highest. I figure I will need a fan that can develop a bit of pressure to push out the vent in enough quantity to make a deffereance. (Man I hope I'm spelling okay)
I'm thinking of putting a squirrel cage type blower fan right at the vent so 1 it will take care of the 90 degree turn and 2 it should develop more pressure. By being right at the vent it should be most effiecient and also the cooking junk won't pull through the motor I plan to add a a filter to catch the grease just before the intake on the fan.
Oklahoma what are people's thoughts? Will the Air only vent combined with a correctly sized squirrel fan move enough air to exaust the cooking steam etc?
Will I need to add a second vent to have enough flow? What size fan should I use to maximize efficiency when combined with the air only vent?
Any su suggestions welcome.
Ideally I'd like to move enough air that with ports hatches closed I am taking care of the vast majority of steam etc.
thanks and sorry if my typing is all over the place ....I wish I could see what I'm typing :-(

[Pelagic]

Is there a way you can install a small opening deck hatch above the stove or galley sink?

It will naturally remove the steam when the weather is good. When lousy, I don’t think a bit of steam is an issue

[Dockhead]

My boat has got powered galley ventilation as originally built. I never thought it was something I would need, but after having it, I would not want to be without it.

It is constructed exactly like the engine room ventilation and using the same materials. It uses an in-line axial-flow blower and large diameter flexible hose, I guess it's 6" or so. It exhausts out the transom.

It transforms life in the galley while cooking, especially when frying something (ugh!), or in cold weather when propane combustion products would otherwise produce a lot of condensation inside.

[David_Old_Jersey]

Dockheads system sounds kinda awesome - I guess one of the benefits of being on 54' of boat!

My starting position would be looking at a Cooker Hood used domestically, not to replicate it exactly onboard! but to get an idea of the volume involved. My gut says that whatever you are likely to install (especially on 33 foot of boat....6 inches (plus?) of exhaust fan is a lot to install and hide!) won't create something that copes with serious cooking when totally locked down. And certainly if possible my first move would be an opening hatch above the galley - of course fans / blowers will also help, just I suspect won't be a magic solution.

[mischief]

Hey I hope this picture uploads. If it worked, it is before I started to install my new strip headliner. The vent hole is now directly above the port window. Just tothe right of the stove. There is minimal deck space directly above and all my vents have to meet my scrutiny on placement so that they are not in my way while moving around on deck. So far out of the 9 vents installed none of them effect the way I move about or where I place my feet. However even if I put the vent to hog the space above deck there would not be any more room as the genoa track runs through the same space.
I definitely want powered ventilation and I know I cannot hide it so I will work with that. I plan to use some copper above the range to make a bit of cowling to help guide the steam so that the fan can extract it.
My biggest concern is if I'm heading down the right path leaning towards a squirrel cage type fan and deciding what size would be most efficient for the system. I feel like even though an axial fan is often more efficient, in this case with the more resistance / higher pressure the cage fan will ultimately be more efficient per volume moved through the system. Is that correct or have I misguided myself? I think the air only vents are 3.5" internal diam and then there is the typical dorade path the air must travel through however it is more compact so the resistance is higher. I was thinking about using a squirrel bilge blower but maybe I should be looking at a large squirrel computer fan or two? Or should I use an 3" rule inline blower with a 90 degree elbow?
Does anyone know how many CFM I need to move to extract the typical cooking steam etc on a boat?

[Just a Tinch]

Vetus makes a nice fan that moves a lot of cfm...uses very little power, has two speeds.. Not expensive. You could mount it on the inside without any problems.

[ardoin]

I have a dorade vent above the stove and fan mounted in the corner. I also have a hatch in the center of the galley. This works great until I make roux for gumbo.... At that point I'm always at risk of setting off the sensors and shutting down the propane fuel... Otherwise, it works very well as it keeps the fumes flowing. I do have to clean the headliner in the galley more often than other areas because, like it or not, you will get more oil in the air near the stove.

[mischief]

I should mention I have a fan that can move air out the companion way and a 4" rule inline blower that can move air out the porthole when appropriate.
But I would like to maximize use of the Air-only ventilator I have installed.
Here's the specs
Air flow Ø 65, mm Cut-out Ø 95, mm
Free flow area 24 cm2
Dimensions 68 x 230 H x W, mm








So with the construction there is a lot of restriction in flow so I feel I need a high static pressure fan. But how high? The higher the pressure than either the higher the energy use or the lower the flow. I'm sure there is a point where the optimal flow vs pressure for this type of vent is met resulting in the most possible flow for the least energy possible. But without a flow measuring equipment and a plethora of fans to test I have no idea where to begin how much flow should I shoot for? 80, 100, 150, 30?
Energy used I would like to keep it under 3a on a 12v system. But striking a balance is more important to me. For example if I could get 90cfm for 2a or 85 cfm for 1a, well I would go for the 85cfm.
I mean there's no point in putting a 3a 90cfm centrifugal blower if It only moves 75 cfm and a 1a 65cfm axial turbine fan gets all 65cfm through.
I hope this makes sense.

Your probably thinking what's the big deal, but when it's cold, windy, pouring outside and were cooking below, the cockpit clears are down or there's people up in the cockpit and we don't want to blow all the cooking byproduct up to the cockpit. Well having a good source of foul weather ventilation would make a world of difference.

Sorry about the long wordy post. :-/

[Hudson Force]

Originally Posted by Pelagic

Is there a way you can install a small opening deck hatch above the stove or galley sink?

It will naturally remove the steam when the weather is good. When lousy, I don’t think a bit of steam is an issue

We follow this plan,- a big deck hatch opening into the weather protected area under the bimini covering. This is simple, passive, effective and no one seems to mind the smells of food being prepared.

[daddle]

This SC50 has a companionway-type hatch over the galley. Opening it is part of the morning coffee ritual. Also one can cook and with one step up check for traffic (well for me, the little cook needs all three steps up).

If you can, put a big opening hatch somewhere above the cooktop. A world of difference in the tropics. All the steam and heat flies out the opening.

[GrowleyMonster]

Be aware that it is not only steam passing through your vent, but also grease splatters and vapors. In time your vent can get coated with grease, and in the event of a stove flare-up it can present a major fire hazard. Keep your vents clean, and keep a dry chem fire extingquisher in the galley.

[mischief]

Thanks Daddle,

It's hard to see but in the picture of my galley above you will see the headliner directly above the stove. This is the width of the deck in that section and the part you see beside the headliner towards the center of the boat is below part of the cockpit surround. So there is no way to put a hatch there.

Also re grease etc in vent. I absolutely agree and plan to have a small grease filter at the intake of the fan plus the air only vent is fairly okay to pull apart and clean every so often. The fact I can not get a hatch near where I would need is the reason I need to figure the correct extraction fan for the vent I have.
Again for use in Inclement weather or while closed up sailing.
Cheers

[vtsailguy]

Did you know that the Air Only has their own fan that fits right on... Called Breezy?

I am curious how the Air Only's have worked out, I am looking at them as well for a solution. They seem easier to install (you don't need a dorade box), but you say that the airflow is constricted?

[vtsailguy]

I am also looking at a fan from sv hotwire that fits over the porthole. Looks to be a bullet proof solution for a galley.

[mischief]

Originally Posted by vtsailguy

Did you know that the Air Only has their own fan that fits right on... Called Breezy?

I am curious how the Air Only's have worked out, I am looking at them as well for a solution. They seem easier to install (you don't need a dorade box), but you say that the airflow is constricted?

Yes I have also purchased several of the breezes but in essence they are very small draw standard muffin fans.

I would say that my Air only vents passively move about 1/3rd the air that a similar sized traditional dorado vent set up would pass. Thus I installed a total of 10 of them.

So far they seem to pass enough air passively that since their install the boat is always fresh even when closed for long periods.
In future (currently being done) I am going to run 4 muffin fans off a separate circuit connected to 4 extracting air only mushroom vents. 2 will pull air directly from the bilge. 2 will pull air through the cabins. I also have a self contained day night solar vent that will pull air through the compost toilet.

Other vents will have fans on our primary wiring circuits to aid in ventilation while sailing heavy weather where the boat is closed up.
Hope that helps.