Airing out a heavy hull

Thread starter #1
Picked up a mint condition '73 sunfish in July. I sailed the boat all summer knowing it was was heavy and needed to air out the hull this winter. I am going to cut a hole in the front of the cockpit for an inspection port. My question is, would it be a bad idea to let it air out over the winter outside? The boat will be flipped upside down on a rack outside in New Jersey. Would this be a bad way of airing it out?
 

Webfoot1

Active Member
#2
If the temperature is at freezing nothing is going to happen. Winter is the
best time if you have it in a heated area. I did do this to a Sunfish in a unheated
pole barn and I could smell it drying out over the winter. It was a very slow
process. Two inspection holes and a muffin-fan are what's needed to get
the job done in any reasonable time frame. If you go with the 60 watt light-bulb
method you'll probably get best results for winter time.
 
#3
Some observations. To get good air flow, you need to install two deck ports. I recommend that you install a 6" dia, deck port centered between the forward edge of the dagger board hole and aft of the inner "V" of the splashrail (coaming) and a second 4" dia deck port centered on the aft deck, under the tiller about 2" - 3" forward of the aluminum hull/deck trim on the transom. Cover the aft opening with 1/4" hardware screen held on by Gorilla tape to keep critters out of the hull and tape a 6" duct fan in the forward port. Turn the hull upside down on sawhorses, turn on the fan and run it until May. You can find the duct fan in a Lowes or Home Depot store for under $20. You can also speed up the process by installing a 40 watt light bulb inside the hull before you install the fan and covering the hull with black plastic to absorb heat from the sun (you do get sun in NJ in the winter, right?)

Next May, do a leak test and find out where the water is leaking in. The usual locations are any visible worn or damaged areas, the bottom of the mast hole, the hull/deck joint and the daggerboard trunk, See the Knowledge Base here on the Forum for how to do a leak test. If you don't find and repair the leaks, the drying process is for naught. Check the mast hole first
by filling the mast hole with water right to deck level and seeing if it drains down. This is probably the most common leak area on a vintage hull as the mast rotates at the base and grinds holes in the bottom over time. It is an easy fix by drying out the hole and pouring thickened epoxy into the hole to seal up holes in the bottom.

Alan Glos
Cazenovia, NY
 

L&VW

Well-Known Member
#4
Picked up a mint condition '73 sunfish in July. I sailed the boat all summer knowing it was heavy and needed to air out the hull this winter. I am going to cut a hole in the front of the cockpit for an inspection port. My question is, would it be a bad idea to let it air out over the winter outside? The boat will be flipped upside down on a rack outside in New Jersey. Would this be a bad way of airing it out?
Winter air is best for drying. "Airing it out" would be sufficient in New Hampshire, as that's exactly what my ex-racer '76 Sunfish gets treated to every winter season. :cool:

"Forced air" would be a surer approach. As above, two ports ducting air would be the most efficient. (But one "forced air" port can work).

A six-inch port ($15), a 4" muffin fan (($8), and 3-feet of 4" plastic dryer-duct ($6) can be inserted to circulate outside air through the hull. (Direct the duct forward, where most of the foam is located, or off to one side of the cockpit). Locate the Sunfish in direct sun, and secure it against sudden winds—such as the disastrous winds NE states experienced last weekend. :eek:

If the location of your rack rules out an extension cord, inexpensive solar-powered fans are available—or you could cobble-up a dorade out of PVC pipe.

More: Heavy Sunfish | SailingForums.com

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mixmkr

Active Member
#5
Typically lower humidity months like the winter are enough. Fans and extras aren't a requirement but will definitely help. 2 inspection ports would be best for sure. Front and aft cockpit walls would be great if you dont want them on the deck....but those locations dont access areas you might normally repair.
 
#6
Hi NJ Boater,

I think the short answer is "No" for two reasons:
  1. Cold air holds less moisture than warm air, but the humidity levels fluctuate like in the summer, and the drying times aren't going to be that different. If there is snow on the ground, the humidity will be kept on the high side. Now if the boat were moved inside, that same air would be warm and it would be "relatively" dryer even though the "absolute" humidity hasn't changed a bit. That difference in relative humidity is what makes people think that winter air is dryer. They're right, but only when the outside air is indoors and warmed up. That difference is why it's easy to dry things out over the winter, but only if what you are drying is warmed up and indoors. Once the temperature is below freezing, then you are relying on "sublimation" which is the direct change from a solid to a gas. That's a really slow process when the ice crystals are in the foam. If you could place a light bulb in the boat it would dramatically speed things up as the relative humidity in the boat would drop. But then you have the next problem.
  2. Likely the boat will be stored upside down. Humid air is lighter than dry air, so it will not ventilate the same way as is if the boat is right side up. You can overcome that problem with a fan as others here have suggested, but then you have extension cords running through the snow and rain.
All just my opinion of course.

Best of luck.
 

Webfoot1

Active Member
#7
Well, logic would see to indicate that if you want outdoor warm forced air
in the winter time you hook the boat up to the dryer vent outside your
house. Easy enough to duck-tape a flexible dryer hose to the house vent and
the other to the inspection port. That's a pretty high volume of air and a couple
hours should get some results. I use to work in a factory that made foam blocks
and the buyer could order the blocks to be stored in a hot-room for 24 hours after
manufacture to dry them out. Anyway, just make sure your wife does not do a load
of laundry. I've never tried this and I don't think anyone has so your on you own
if you do.
 

L&VW

Well-Known Member
#8
Well, logic would see to indicate that if you want outdoor warm forced air
in the winter time you hook the boat up to the dryer vent outside your
house. Easy enough to duck-tape a flexible dryer hose to the house vent and
the other to the inspection port. That's a pretty high volume of air and a couple
hours should get some results. I use to work in a factory that made foam blocks
and the buyer could order the blocks to be stored in a hot-room for 24 hours after
manufacture to dry them out. Anyway, just make sure your wife does not do a load
of laundry. I've never tried this and I don't think anyone has so your on you own
if you do.
"Duck" tape evolved from a tape used to secure metal air-conditioning ducts together. It has been called "Duct" tape ever since HVAC became common after WWII. "Duck" tape is also a recent brand name. When I see "Duck" tape, I think of this image:

 

Webfoot1

Active Member
#9
Strangely, Duck-Tape never had anything to do with heating ducts. It was a WW2 invention
to keep water out of ammo boxes. Berkeley Labs did a 1998 test to see if you really could
use it for duct work and found that of all the tapes tested after 3 months only the
Duck-Tape failed. With it's low tensile strength and gummy adhesive Duct-Tape
is indeed a strange bird.
 
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