Fan Of Dorades Or Fan Of Fans?

[linnupesa]

Hi y'all comfort zone engineers

Heat and high humidity is misery. At high airflow fans will reduce the oppression.

and dorades and vents will help passively, but not nearly enough under calm conditions.

At anchor the various air scoops seem to be popular, but again, they need some wind.

Solar powered fans work, but how well really? Perhaps it's only the placebo effect that

makes them popular.

What has worked best for your own situation, where you can definitely state your new fix

has resulted in a marked improvement in comfort level? And yes, I can also run the genset

and switch to "max. cool" and "Fan: high", but that would be in causa extremis only.

Though I have loads of hatches that I can open, squalls or persistent rain don't always allow me

that luxury, so I'm looking for some other solutions. The dodger and bimini shelter the

open cockpit hatch from most rain, but there should be a cross-draft really, to be effective.

Also, I'd like the solution to be somewhat splash-proof, so dorades spring to mind. What I

have not seen is using a keel-stepped mast as a conduit for ventilating. Would slits or holes

placed JUDICIOUSLY weaken a mast too much? There already are halyard exit holes and

between the mast step and the deck there should be mainly compressive forces. Having

a few more holes ( below the partners ) should not materially affect the design strength. I

know already some rain gets in, so why not a bit of air coming along for the ride too?

Another option I thought might be to make the currently fixed saloon windows openable,

with a horizontal hinge at the top. The hinge part would need to be sealed, so water

from the cabin top would not enter. With the saloon ports at head height, that should

create an air flow where it would be most... well, efficacious. ( any links to such

types of windows, off-shore rated though?)

A penny for your thoughts and ideas. I'll be heading to the Florida Keys soon and the

current weather is still plenty nice to start some more projects, let alone to finish them.

Many grateful thanks etc etc in advance.

Ivo

[redbopeep]

When at anchor, full boat cover/shade will make an incredible difference. My sister-in-law lived several years in the Florida Keys and boated throughout Florida and parts of the Caribbean and can attest to this. The moment they anchor, up goes the full boat sun-cover. Makes a big difference.

I'd skip the mast-as-a-draft as it is unlikely to be incredibly useful to you. Warm air rises, yes, and getting circulation through the boat is great for keeping things cool. With a wooden boat as we have, there are methods of circulating cool air from the bilge up through the spaces between the hull and ceiling to vents provided up where the ceiling meets the overhead. Warm air rising creates a natural circulation. However, that won't be enough to keep the boater happy and feeling cool. We have a couple cowl vents (you see these atop the Dorade boxes. the "Dorade" is simply the baffled box which prevents water from entering the boat, the cowl vent is the thing which scoops the air into the box and into the boat) in strategic locations. We also have several butterfly hatches that can help scoop and direct air downwards. Finally, with that whole warm-air-rises theory, we bring air into the boat in the forward section with hatches and air scoops and it flows back and up through the charthouse/companionway door. We can note, on most days, that the air temperature at chest height in the galley/main saloon area is 5 to 10 deg F cooler than in the charthouse because of this whole heat rising thing.

One of our cowl vents sits atop a Dorade box in the back of the steering housing. It works well to move air in-or-out of the aft section of the boat.

Fans. We have a couple 12V computer fans that move a bit of air where we find it "stale" and worry about mold. That is the very front of our boat near the stem forward of the anchor locker. However, that isn't for comfort, it is for boat condition and keeping mold away. It does work. We also have a couple household fans that we've used to really direct alot of air through--but they are not by any means efficient. One of my butterfly hatches is directly above the stove so the heat of cooking rises directly out and doesn't stay in the boat.

Living on a hot/humid boat is different than living in a hot/humid house, yes.

I've had more than my share of living without using A/C in hot, humid environments --20 years in all. We only used A/C when friends/family visited us. We lived in Florida 1 year, Japan 2 years, and the worst heat/humidity we lived in was for a total of 4 years in the heavy heat and humidity of South Texas summers. Commonly 95F+ and 80% to above 95% humidity. Hot, sticky, yuck. We did NOT use air conditioning at the time for reasons of personal preference. We spent 13 years in Washington DC including the hot, humid summers w/o using A/C I detest those conditions but also hate AC.

Back to being aboard a hot/humid boat--it is my experience that the smaller the boat, the more important it is that you have complete shade over the boat to help provide cooler air and some sort of insulation in the overhead so the sun beating down on the deck doesn't just turn the boat into an oven. The larger boats have more stratification of air and provide a little self-ventilation. My sister-in-law's boat is a small motorboat with barely a v-berth space below. It is incredibly hot compared to her friend's 45 foot sailboat. I've spent time on both at anchor and the sailboat is always cooler even when there's no airflow at all. I've done a little boating in the Philippines 6 weeks during the rainy season (May-June) and it was pretty miserable aboard. No amount of fans helped there. Just too much humidity and you just had to suck it up and deal with it. Of course there we could jump into the water or pour water over ourselves at anytime to help cool a little bit.

I hope this mind-dump is somewhat useful to you,

Fair winds,

[linnupesa]

Thanks Redbobeep

Yes, the full cover I have found very effective too but of course it is impractical under sail. A hatch above the stove is also a must and a godsend when you abso-tootely need to grill those char-nitas right then and there, when it's stifling hot outside.

Dorades, I understand the difference between the box and the air scoop part. Not all dorades are created equal though. The big and ugly ones are likely the most effective, having everything in large diameter. Bigger definitly is better here and any argument about "its the motion of the ocean" is humbug imho. Some dorade boxes have 2" and 3" diameter pipes leading below deck behind the water baffle. Quite often there still is the bug-screen or a central knob for screwing down a sealing

plate, which all will slow down circulation. One advertised vent type even has small ping-pong balls to float up and seal out deck slosh, the air having to take quite a tortuous route. Rant: The trouble with much marine stuff these days is that it looks OK on paper but in reality is hardly up to the task.

The smaller the vent diameter, the less the flow. ( it has something to do with a quadratic equation ) So, would I be correct in assuming that only a 4-5" ID pipe or larger will really produce some noticable relief? Using the mast is appealing to me, as it already is the biggest gozinta into the boat, there just needs to be a way to get the air out. The mast is really a tall chimney just looking for a job and as chimneys go, the taller it is the better is the draft that it creates. It's that convection thing again.

I've put in a few Vetus type vents, a simple round saucer above the round vent pipe, which do keep out all but the heaviest rain splashes and which can be screwed shut for a total seal. However, they are at deck level and only a few inches in diameter. While I can detect some air movement and they will therefore combat mildew, person-comfort wise they seem to be toys, little more. Of course, they will not snag lines as a full dorade with an elevated schnozzle would.

Talking shade, deck insulation comes to mind. Your wood or my balsa core fibreglass are fairly good insulators. White deck paint is hard on the eyes but also helps to reflect heat. However, in the tropics where diurnal temperature changes are minimal, both in- and out-side soon reach an equilibrium. Especially when the sea temperature is high there is no cooling to be expected from a "cool" bilge draft.

So, what other active methods of cooling are out there that will create draft or air flow?

Ivo

[redbopeep]

Your hatches should allow some air movement. And, indeed, the larger cowl vents are going to be more effective at capturing air. Ours are 4" or larger diameter through the deck, all of them. The Dorade aspect must be designed with similar area or it is useless, yes. We have bronze deck plates that screw into place of the cowls so we can use those if we're in rough seas.

I seriously doubt that the airflow provided by your mast-as-chimney would be worth the risk associated with messing with your mast. If you think it's actually worth doing, first buy some cheap dryer hose and haul it up a shroud or your mast, stick it in a porthole and see if it does what you think it will do. I doubt it will be worth it.

If you're underway, you should have air-movement galore which may be harnessed by your hatches, cowl vents, and such. If you're at anchor, then scoops and what-not are helpful. In fairly still air, we have taken a tarp and funneled an amazing amount of air down into our front hatch (a scuttle hatch) on the boat. We do not have a full-boat cover. Our plans take us to higher latitudes away from the hot climate that you must be sailing in. Finally, if you really can't deal with the heat, fans, A/C and your genset are solutions that may work for you.

Fair winds,

[linnupesa]

I like your ideas... I can already see the marine equivalent of the men in white coats racing up to whisk me away when I to try to funnel down a tornado with my dryer hose.. Definitely worth the experiment if I can find oval hose with a 8x15 opening. Here tornado, here!

The 4" or greater diameter of your vents makes absolute sense. It seems that the bigger and bulkier the solution, the better. (Like the tarp idea.. and no, not the troubled assets relief fiasco) The higher lats also make sense but I haven't yet found a published sailing route from Capricorn to Cancer that won't make the butter melt. One does have to deal with those areas, but I agree, Maine or the PNW do not have that issue. There you need a heater much of the time!

[danblu]

Best I've found is a naked , beautiful woman to sweetly fan my body with lavender scented feathers Seriously though, I really don't think there's much that can be done that is not already mentioned except for altering one's state of mind. If you can get your mind around this its worth a try. Yoga relaxation is really cooling for the body and also a breathing tecnique where one rolls the tonge into a tube like shape and slowly draw air through. Its a last resort for when the women are away

[linnupesa]

Dan

The only rolling I'm thinking of right now is ROFL.

Actually, my thoughts are more for the situations when those nbw's are bickering about having to waft all those feathers around, and in the heat too...

L__O

Now off to practice rolling my tongue but somehow I'll need to keep from biting it all the time....

ouch!

Ivo

[JeanneP]

Our first full canopy while we were at anchor was built for us in Venezuela by another cruiser. I went to a local store and bought a partial bolt of ironing board cover material - the silvered fire resistant material. The woman who sewed the canopy was most impressed with the fabric - it reflected heat and she tried putting a cigarette out on the fabric and it didn't burn or scorch. The drawback was that it was quite heavy, but it kept our deck really cool at 10˚ N lat. Those dark blue canopies that look so attractive on the white sloop were significantly hotter than our not-so-attractive silver canopy. In the tropics, comfort trumps pretty every time.

On this power boat there are large sliding glass doors and big windows that let in far too much heat. In desperation I glued a mylar "space blanket" to very light cotton fabric and cut it to shape to cover the door's glass (at a 75˚ or so angle, it let a lot of heat and sun into the boat). It reduced the temperature of the glass by at least 15˚F.

One other trick we used when the sun and heat was really bad - poured water on the deck. Australians used to build a "coolangatta cooler" - a canvas tube into which meat was hung and the fabric was doused with water - the evaporation of the water cooled it.

Because of nerve damage I only perspire on half my upper torso. The difference in skin temperature on the two sides of my neck was so significant that I used it to give a physics lesson to my niece and nephews. On the side where I perspire, the skin is very cool, on the dry side the skin is fever-hot. The first summer after the damage occurred I walked around pouring water on my head to cool down. Another version of the coolangatta cooler.

[linnupesa]

Originally Posted by JeanneP

Our first full canopy while we were at anchor was built for us in Venezuela by another cruiser. I went to a local store and bought a partial bolt of ironing board cover material - the silvered fire resistant material. The woman who sewed the canopy was most impressed with the fabric - it reflected heat and she tried putting a cigarette out on the fabric and it didn't burn or scorch. The drawback was that it was quite heavy, but it kept our deck really cool at 10˚ N lat. Those dark blue canopies that look so attractive on the white sloop were significantly hotter than our not-so-attractive silver canopy. In the tropics, comfort trumps pretty every time.

On this power boat there are large sliding glass doors and big windows that let in far too much heat. In desperation I glued a mylar "space blanket" to very light cotton fabric and cut it to shape to cover the door's glass (at a 75˚ or so angle, it let a lot of heat and sun into the boat). It reduced the temperature of the glass by at least 15˚F.

One other trick we used when the sun and heat was really bad - poured water on the deck. Australians used to build a "coolangatta cooler" - a canvas tube into which meat was hung and the fabric was doused with water - the evaporation of the water cooled it.

Because of nerve damage I only perspire on half my upper torso. The difference in skin temperature on the two sides of my neck was so significant that I used it to give a physics lesson to my niece and nephews. On the side where I perspire, the skin is very cool, on the dry side the skin is fever-hot. The first summer after the damage occurred I walked around pouring water on my head to cool down. Another version of the coolangatta cooler.

Thanks Jeanne!

Boat industry tycoons, listen up and get some pointers from Jeanne above. You are designing far too much ill-conceived and shoddily executed junk. Then you foist it on the market simply because it is that kind of whiz-glam that suckers in inexperienced Admirals at the boat show. Do I really mean that? Tsk, of course not, just saying....

Yeah, I've often wondered where I can get what some folk must have been smoking... Sliding doors, escape hatches that delaminate and sink boats, acres of glass that then require acres of shades and blinds, saloons large enough for a trampoline but with itty-bitty hand-holds at insane spacing, maintenance items you need to access with a sawzs-all and a crowbar....

The silvered ironing material seems just like space shuttle technology for boats and so eminently do-able. That ozzie cooler however is not a new idea. Here I believe it's called the Cooling-Gut-ta and it works with cold Amstel or Bud's. Apply liberally to hot parts via the intake near the top. There are some experts who even manage prone applications. But then I'm only a green card holder here and do not fully understand all the local mores and lores yet, so cut me some slack with the Coolie-gutta. Some say that one actually first originated in China.

My dodger and sail covers are a tan sunbrella and I often wished they were just white canvas, as in the sailing ships of lore. Gull poop has a much better relationship to white materials as well, it just blends naturally. I also notice radiated heat below the awning, which is a similar tan color but canvas. A mylar aluminum sandwich would make it so much more effective and add barely noticeable weight. How did you find the material held up under UV and rain, wear and tear wise? It is something I'd certainly like to try in a new bimini. It would cover the areas where the crew hangs out most of the time and even a premium price might be worth it . (The old one flew o/b during a squall )

OK, good food for thought.. Quiet, the codger is cogitating now.

Ivo

[JeanneP]

My favorite "stuff" source, American Science & Surplus - where I find stuff for my geeky brother and his geeky sons. And here's the link for the mylar: http://www.sciplus.com/search.cfm?ut...=0&btnHand.y=0

I painted light cotton fabric (cheap muslin bedsheets are a great source of very wide fabric) with "Tacky Glue", a craft glue, and then placed the mylar on the fabric to fuse the two fabrics. Super light. Cheap nylon tent fly's would be another good, very strong source of base fabric.

Finding ironing board fabric is a bit more difficult. To make it affordable try to find a surplus place that sells bolt ends. Because the silvered surface reflects almost 100% of the light, UV degradation is minimal, and it was waterproof. The base fabric, though is usually not particularly good quality because for ironing board covers it doesn't need to be. However, the sun canopy lasted for at least 7 years, perhaps more since I can't remember when we had a new one made - which wasn't as good as the old one, fabric-wise.

For sewing, the perimeter should be reinforced with strong twine. Seams are best if they're flat felt seams (the seams on Levis jeans), additionally glued.

[linnupesa]

Originally Posted by JeanneP

My favorite "stuff" source, American Science & Surplus - where I find stuff for my geeky brother and his geeky sons. And here's the link for the mylar: http://www.sciplus.c...x=0&btnHand.y=0

I painted light cotton fabric (cheap muslin bedsheets are a great source of very wide fabric) with "Tacky Glue", a craft glue, and then placed the mylar on the fabric to fuse the two fabrics. Super light. Cheap nylon tent fly's would be another good, very strong source of base fabric.

Finding ironing board fabric is a bit more difficult. To make it affordable try to find a surplus place that sells bolt ends. Because the silvered surface reflects almost 100% of the light, UV degradation is minimal, and it was waterproof. The base fabric, though is usually not particularly good quality because for ironing board covers it doesn't need to be. However, the sun canopy lasted for at least 7 years, perhaps more since I can't remember when we had a new one made - which wasn't as good as the old one, fabric-wise.

For sewing, the perimeter should be reinforced with strong twine. Seams are best if they're flat felt seams (the seams on Levis jeans), additionally glued.

Superb info Jeanne. I greatly appreciate it.

As to the UV, I expect quite a bit to come off of the water and the deck and not only from above.

Seven years is quite a reasonable life if it was outside most of the time. I'm not sure how long Sunbrella would last but I suspect not much more than 10 either.

Ivo

[redbopeep]

JeanneP, Your silver ironing board cover sounds similar to our silver-tent top that we used over our boat in the boatyard. We wanted heat to rise and pass through the tent material so we originally considered black shadecloth from a greenhouse supply store. Then I learned about Aluminet and made a tent from it. It worked wonders at the desert-like dry inland yard where temperatures were in the high 90's in the mid summer. With a greenhouse fogger running under the boat, we had temperatures in the mid-80's that were quite pleasing compared to the yard surrounds. It was quite common for other boat owners and yard workers to take breaks sitting under our boat in the cool and humid shade compared to the hot/dry air outside. We kept the Aluminet but I have not re-cut it into something to use at anchor.

Only pic I could find showing the white tarp enclosure with Aluminet top--look behind the guys!



Aluminet above the boat:



good aluminet info

Someone using aluminet