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Cowl vents, compact dorades


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#1 Diarmuid

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Posted 03 November 2013 - 04:28 PM

We're trying to maximize ventilation for our Albin Ballad, since it will be living in the Sonoran Desert and that's a different climate than Sweden.;) So far, we've added a 19x19 hatch in front of the sea hood, and two opening ports in the cockpit bulkhead.  There's a passive mushrrom vent in the forward head compartment (now a closet), and a forward-opening hatch in the V-berth (not much use underway).

 

We've been contemplating dorades of some sort.  But the coach on this boat is slim & wedge-shaped -- not much space for boxy boxes. Anyone have experience with integral cowl vents like the Plastimo Cool-n-Dry? There's a complicated (but clever) version sold out of Malta as well. Anyone tried these?

 

Or should we just bung two Nicro solar vents either side of mast & go sailing?



#2 SloopJonB

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Posted 03 November 2013 - 04:35 PM

Remount the forward hatch so it opens aft. The little solar vents don't exactly provide breeze below, they just help prevent mould from growing.



#3 Diarmuid

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Posted 03 November 2013 - 04:43 PM

Remount the forward hatch so it opens aft. The little solar vents don't exactly provide breeze below, they just help prevent mould from growing.

I'm working on a double-hinge design for that, so it can be opened either way.:) At anchor, it's nice to have it open forwards, as a wind scoop.  Not sure we want it open in a seaway; a wettish boat, the Ballad. 

 

Albin-Ballad_1-web.jpg

 

(You can see how little deck room we have to play with.)



#4 sailSAK

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Posted 03 November 2013 - 07:05 PM

For $120 you can't really go wrong with the Plastimo.   Start with one...  My boat came with some low profile hand made dorade boxes with 3" low pro cowls on it.  They worked ok in Hawaii, but eventually upgraded to regular size boxes and regular profile 3" cowls.  It made a pretty big difference.  It takes up a little space on deck, but only maybe twice what the Plastimo does.     The more tortuous the path the less air flow you get for the same area...



#5 Moonduster

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Posted 03 November 2013 - 07:36 PM

I've always found that powered fans work much better than passive vents like dorades. I recommend making all your vents draw air out of the boat rather than trying to jam air into it. This means turning the cowls to face aft so they create low pressure in a breeze. But if you want serious airflow, I'd really recommend the powered Nicros over the passive dorades.

 

Good luck!



#6 Alpha FB

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Posted 03 November 2013 - 09:19 PM

First thing I did when I bought my Folkboat back in 2000 was to invest in a couple of Plastimo Cool-n-dry vents. I installed one over the forecabin, the other next to the companionway. The idea was one to get one to force air in, the other to extract - the cowls are always pointed in opposite directions. As a result I have NEVER had any real issues with condensation inside.

#7 Ajax

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Posted 03 November 2013 - 09:37 PM

I goddamn hate cowl vents and dorades. They are a trip hazard, and nothing but a source of a dozen little screw hole leaks to rot your deck core.

They look great on a Hinckley or a Baba, but not so much on our boats.

On a boat like the Ballad, I'd install a couple of Nicros (if even that), and use a chute-scoop or similar device at anchor.

When I motor, I'll prop the forepeak hatch open a bit to catch the breeze. I won't do that while I sail obviously, because the damn jib sheets will try to rip the hatch off.

 

Dia, I know you pay great attention to detail and if you choose to install cowls or dorades, you'll probably do a meticulous job. 



#8 Diarmuid

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Posted 03 November 2013 - 09:44 PM

First thing I did when I bought my Folkboat back in 2000 was to invest in a couple of Plastimo Cool-n-dry vents. I installed one over the forecabin, the other next to the companionway. The idea was one to get one to force air in, the other to extract - the cowls are always pointed in opposite directions. As a result I have NEVER had any real issues with condensation inside.

Maybe a mix of powered vents & dorades is best? Good info, Alpha (and may I say, the Folkboat is the archetype of all sailboats I love. :wub:   The proto Ballad was called Joker, a pointed reference to Hasler's Jester.) What's your impression of the Plastimo cowls? have they discolored or leaked at all? Do you get a pretty good flow out of them?

 

Two things I really like about the Maltese design: the cowl is captive, so it's less likely to get chucked overboard by genoa sheets; and it is made of acrylic-modified styrene rather than PVC, which can yellow & even turn gooey in hot sunshine. Question is whether the little balls will rattle & drive us batshit.



#9 Diarmuid

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Posted 03 November 2013 - 10:14 PM

I goddamn hate cowl vents and dorades. They are a trip hazard, and nothing but a source of a dozen little screw hole leaks to rot your deck core.

They look great on a Hinckley or a Baba, but not so much on our boats.

On a boat like the Ballad, I'd install a couple of Nicros (if even that), and use a chute-scoop or similar device at anchor.

When I motor, I'll prop the forepeak hatch open a bit to catch the breeze. I won't do that while I sail obviously, because the damn jib sheets will try to rip the hatch off.

 

Dia, I know you pay great attention to detail and if you choose to install cowls or dorades, you'll probably do a meticulous job. 

Ajax: aw, thanks.  I'm kinda nutso about isolating deck cores from water intrusion.  You should see the core-cutback, fill, and curb job under the new hatch.  In fact, here it is:

 

10656452224_e5a3a3a2a0_o.jpg
 

Apologize for the uneven, temporary paint job; it all has to come off next summer, before getting 2-part urethane. You can see the bulkhead ports, new winch pads (solid core) and minty fresh little raised pads for the handrails & chainplates. And this is 1"t phenolic, ready for stand-up blocks,  where leaks had degraded the mast collar area:

 

9347083639_18c8e8654a_o.jpg

 

We'd isolate any cowl/shroom vents completely.  Some PO installed a solar Nicro vent where the Bomar hatch is now; it let in quite a bit of air but no light to speak of. There seems to be a trend of mounting powered vents in the middle of hatch lenses these days, which might be an option. We won't really have room for granny bars around our cowls, unless we go with just one in front of the mast....
 



#10 Ajax

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Posted 04 November 2013 - 12:47 AM

Nice work!

#11 Alpha FB

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Posted 04 November 2013 - 05:33 AM

The quality of the Plastimo's has been fine, but after a few years the locking mechanism on one broke. On most days you can clearly feel the air flow. One gripe I've had with them is that the front one regularly catches the jib sheet while tacking. I've solved this by tying a line over it to lead the sheet above the vent - works most times,but ideally I'd need some sort of small permanent frame over it.

#12 sailSAK

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Posted 05 November 2013 - 05:16 AM

I've always found that powered fans work much better than passive vents like dorades. I recommend making all your vents draw air out of the boat rather than trying to jam air into it. This means turning the cowls to face aft so they create low pressure in a breeze. But if you want serious airflow, I'd really recommend the powered Nicros over the passive dorades.

 

Good luck!

 

You have to have somewhere for makeup air right?  If your companionway is pretty tight on most boats this would mean the bilge, anchor locker or engine space right?  My philosophy has always been drive the bad air out, or as I was taught in the Navy Machinist Mate school "it is always easier to blow than suck".  Its not as bad as it sounds, really...



#13 Bob Perry

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Posted 05 November 2013 - 12:02 PM

Look at the vents that Vetus offers,



#14 Diarmuid

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Posted 05 November 2013 - 05:20 PM

Look at the vents that Vetus offers,

Bling! Quel bling. Gorgeous, possibly an upgrade for the future.  Scale might be a bit off for this boat, as the Vetus stuff is a bit taller than some others.  Good for air collection, tho.

 

Looks like H-R is using Air-Only vents & cowls on their new boats; think I'll order one or two & test them out.:) One benefit of a prolonged refit at 7500': before the boat leaves the yard, we'll know if certain products are tough enuf to survive extreme environments. I primed and painted the cockpit hatches with System3.  Two years hence, we'll decide whether that's the paint for the hull.

 

Laminating the water tank today. Yay! Progress. 21*F and 4" of fresh snow out there -- good day for indoor work.



#15 Ishmael

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Posted 05 November 2013 - 05:24 PM

Look at the vents that Vetus offers,

Bling! Quel bling. Gorgeous, possibly an upgrade for the future.  Scale might be a bit off for this boat, as the Vetus stuff is a bit taller than some others.  Good for air collection, tho.

 

Looks like H-R is using Air-Only vents & cowls on their new boats; think I'll order one or two & test them out. :) One benefit of a prolonged refit at 7500': before the boat leaves the yard, we'll know if certain products are tough enuf to survive extreme environments. I primed and painted the cockpit hatches with System3.  Two years hence, we'll decide whether that's the paint for the hull.

 

Laminating the water tank today. Yay! Progress. 21*F and 4" of fresh snow out there -- good day for indoor work.

 

Good luck with that. I used to sell System 3, along with "traditional" paints, and I don't think we ever saw it stay on any surface for longer than a year no matter what. System 3 blamed the prep, the substrate, global warming, and anything besides the paint. I personally was interested in it, but watching that horror show unfold cured me. 



#16 Black Jack

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Posted 05 November 2013 - 07:01 PM

Bob is right about Vetus cowling and vents. Stainless steel will look great for years to come and have nice dorade boxes and screens. You can always remove them too and replace them with plastic once you are going to sell boat keeping them for the next boat.
 
IMHO the other plastic ones looked like they were picked up at wallmart regardless on the beautiful skilled fiberglass around it to hold it in a watertight secure position. They also tent to mold in wet and misshape after a season of direct solar heat. 



#17 Diarmuid

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Posted 05 November 2013 - 08:29 PM

Good luck with that. I used to sell System 3, along with "traditional" paints, and I don't think we ever saw it stay on any surface for longer than a year no matter what. System 3 blamed the prep, the substrate, global warming, and anything besides the paint. I personally was interested in it, but watching that horror show unfold cured me. 

Hmmm.  Interesting info.  That's why we're testing it this way, tho -- if it totally flakes off, we're out a grand total of about $40.  Beats having $1200 of hull paint & undercoat slough off. Another Ballad owner just did his entire boat in Sys3; it will be useful to follow his experience with it. We get 320 days of brutal UV a year, plus a temperature range of about 120 degrees F.  Good testbed for paints!



#18 whinging pom

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Posted 06 November 2013 - 10:04 AM

Nice boat!  I used to own an Albin Ballad, hull no. 104.  A real rating bandit under IRC.

 

I fitted a vetus mushroom vent right in the very front of the foredeck. It replaced a navel pipe.  It certainly helped with the ventilation at rest, mind you this was sailing in the English Channel and keeping water out was more of a priority!

 

Do keep an eye on the steel work under the mast step and the bulkhead bolts.  On mine, the glass spalled away as the steel rusted and allowed the mast to drop 2".  As this happened the bulkhead tore away from the hull...

 

Sold her for "Spares or Repair".  



#19 Diarmuid

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Posted 06 November 2013 - 04:21 PM

Nice boat!  I used to own an Albin Ballad, hull no. 104.  A real rating bandit under IRC.

 

I fitted a vetus mushroom vent right in the very front of the foredeck. It replaced a navel pipe.  It certainly helped with the ventilation at rest, mind you this was sailing in the English Channel and keeping water out was more of a priority!

 

Do keep an eye on the steel work under the mast step and the bulkhead bolts.  On mine, the glass spalled away as the steel rusted and allowed the mast to drop 2".  As this happened the bulkhead tore away from the hull...

 

Sold her for "Spares or Repair".  

I read someplace about a Ballad that had its bulkhead come adrift (during a Fastnet?) and nearly crack the hull like an egg -- was that #104? We'll be tabbing all bulkheads in properly, both sides, and thru-bolting them. Trying now to get the mast plate off to inspect the truss; months of penetrating oil, as the machine screws are pretty much welded to the alu plate. Any ideas how best to inspect? I have access to a endoscope/wall cavity camera -- can I just drill a hole in the cabin sole? It's been a Great Lakes boat most of its life, so corrosion mostly hasn't been an issue, but now is the time to peek at that truss.

 

You exactly understand the venting issue we're dealing with.  Like most Northern European boats, keeping out icewater was prioritized over airflow. Different in the tropics.:)   We crave more light, brighter colors, tons and tons of airflow.  Mushroom vents or solar fans are fine for air exchange & will keep mold down, but they can't move the sheer volume of cooling air a directional scoop will. 



#20 Diarmuid

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Posted Yesterday, 04:24 AM

Update: We bought two of the Air-Only cowl vents and have got one installed, using the existing passive mushroom location. It is almost the only place that they could go without being in the way of everything. Air flow is so-so: with only 3.5" inside diameter and all the various balls, louvers, and baffles, there is some loss of efficiency over the traditional box&baffle.

 

Modus shipped them from Malta (via Singapore), so they took awhile to get to the US.  Delivered cost, $200 for the pair. They were soft-packed two to an envelope, not in cardboard boxes as shown on eBay.  A few fasteners were loose in the envelope. The moldings are exceptional: clean, no flashing, everything perfectly aligned.  The units require more assembly than you would think, and the steps need to occur in sequence.  The yellow O-rings are tricky to keep in place during assembly.

 

Today I stuffed a blue shop towel up into the vent from below, picked up a 5-gallon bucket filled with water, and launched the contents as hard as I could -- straight down the throat of the cowl. :o The towel was knocked out by the air blast, but except for a few drops on it and the shelf beneath, no water went below. So they do keep water out.  Whether they supply the airflow we need, won't know til warm weather comes & the second vent is installed.






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