Black Canvas - too hot?

philwsailz · Jul 30, 2009

I have cautiously been adding black canvas to the sailboat, ( sail cover, halyard bags, tiller cover, mooring cover) and also have a black bimini on the powerboat. I had similar concerns, but from experience with the the bimini on the powerboat, I think black is an okay color with the caveat that you want to maintain ventilation.

I think the difference between the canvas application and the automotive model is that with the auto, the black heats up, but is trapped inside the vehicle, with zero circulation. So, you have a closed loop system. The seats heat up, they heat the air, the seats get hotter....

Your boat with a black bimini and dodger would be more like a black car with a white interior, with the windows down. To me, the black bimini on the powerboat blocks more light, stopping more of the heat. I have sat under white fabric, and felt shaded, but also still acknowledged that a lot of sun was getting through.

I have a fitted mooring cover I made this spring. The boat seems a little warmer down below just after opening her up, but I think I can atribute it not only to the black cloth laying on the deck, but also to a greater extent, to the effect of having the hatchboard ventilation slots covered. I need to add a solar ventilator to keep things fresher.

To the plus side, I have no wasps or other flying stinging creatures in the boat this year!

I would appreciate hearing what others have to say, as I want to add a bimini to L.L.attitudes, but I want to do black as well. Post up folks!

RichH · Jul 30, 2009

Check with your fabric supplier for some of the newer 'duplex' type fabrics - dark color on one side, light color on the reverse side. These are 'thicker' than standard Sunbrella and afford so R-value increase due to the greater bulk/thickness.

Dark colors 'radiate' (not conduct nor convect) heat downwards, although dark colors are easier on the eyes when they 'shade' them.

You also may want to consider a different fabric than Sunbrella as the 'water proofing' (a phospho-fluorine compound) that was originally used is rapidly being phased out worldwide due to 'grave environmental concerns' ... hence the appearance of 'urethane coated' acrylic fabrics or fabrics where the individual fibers of the fabric are coated with silicone, etc. My observation is that Sunbrella fabrics do not have the 'water repellence' in comparison to just a few years ago - just an opinion.

Dan Johnson · Jul 30, 2009

I have black canvas...

for my bimini, dodger, mainsail cover, hatch covers, wheel, binnacle, and headsail cover when furled. I have not noticed any appreciable difference of heat beneath this canvas color versus the dark navy blue of other boats I have been sailing on.

I have a digital temp sensor and will take readings under the canvas on several boats besides my own next trip to the boat for comparisons.

Rich: my canvas is close to a decade old and in all probability made from Sunbrella fabric. My dodger began dripping through two years in every rain. I treated it with spray-on Scotchgard but found that it only lasted about a month before soak through occurred again.

Over the winter I read about a spray-on fabric treatment available at WM stores (it was either in CBM or Prac. Sail.) and gave it a try. It really works! On the July 4th weekend I treated the dodger. I didn't treat one panel of the dodger as a control check. In the downpour that occurred on Sunday afternoon that panel contined to bleed through, but the top and all other panels beaded up like car wax. It's worth every penny of the reasonable price for the liquid spray bottle (under $10 if I recall).

Ron20324 · Jul 30, 2009

On my B235 I had an umbrella with alternating whilte and blue panels in a fishing rod holder to use when at the tiller. There was an obvious difference in heat, lowest under the white panels, hotter under the blue. That was the first time I experience the actiual difference in heat buildup due to light/dark colors. My present B323 has the Seagrass green bimini, and it can be hot up close to the canvas- like when steering. Of course, the breeze blows it away, and it's not a concern to those who are sitting. I think a dark-color dodger will really heat up.

I've said this before, but Dan at the Annapolis Sailrite turned me on to a good idea, and I'm presently making my dodger his way. Instead of a one-piece dodger like you've always seen, make like a bimini-dodger first. with zippers around the edge, make separate front/side panels to zipper on. This would be pretty much the same as if you made a full cockpit enclosure zippered to the bimini top. With the removable front/side panel, you can store them out of the sun and they'll last alot longer. For the side panels, I am making the standard window-type, but also a set that can zipper on and extend out to the lifelines and up to the filler panel. There's many options with this plan.

zeehag · Jul 30, 2009

there is solar screening that works well withj sunbrella or brand x cover material---make a panel and frame it with the sunbrella for a tarp over the boat in hot sun---best of both worlds and keeps air flow excellent--pretty, too.....just a thought~~~~~~_/)~~~~~~~

Stu Jackson · Jul 30, 2009

Dan, need a name...

Dan Johnson said:
Over the winter I read about a spray-on fabric treatment available at WM stores (it was either in CBM or Prac. Sail.) and gave it a try. It really works! It's worth every penny of the reasonable price for the liquid spray bottle (under $10 if I recall).

Dan,

Please, if it is so good, please tell us, don't keep us in suspense,
what is it called so we can go buy it???

I am looking for something just like that which works!

Help, please.

Also, now back to the topic about:
BLACK CANVAS and HEAT.

RichH · Jul 30, 2009

Cpt. Jon said:
RichH - what are alternatives (brand names) that offer a better solution than Sunbrella? I know Hermit Scott is looking into doing his canvas as well and if he hasn't purchased Sunbrella already, he might also like to hear.

I was always under the impression that Sunbrella offers the best solution and the other options out there may be cheaper but won't offer the protection and last as long as Sunbrella.

thanks!

Stamoid - vinyl coated acrylic

Sunbrella Plus - urethane (one side) coated Sunbrella - probablly will replace std. Sunbrella when all the water proofing compounds become unobtainable.

Sunbrella Supreme - standard Sunbrella with an added 'flocking' layer - fabric sides can be different colors

TimCup · Jul 30, 2009

John, to answer directly, yes.

The dark bimini/dodger will definitely be hotter underneath it. The heat will be obvious, the closer you are to the underside, the more you will feel it. In my experience, once you're about a 18 inches away, it makes no difference. Of course, I'm assuming the boat is at anchor or moored. If you're underway, the breeze will make it a non-issue (except mabe DDW- I HATE going DDW because apparent wind won't get the heat away!).

cup

zeehag · Jul 30, 2009

TimCup said:
The dark bimini/dodger will definitely be hotter underneath it. The heat will be obvious, the closer you are to the underside, the more you will feel it. In my experience, once you're about a 18 inches away, it makes no difference. Of course, I'm assuming the boat is at anchor or moored. If you're underway, the breeze will make it a non-issue (except mabe DDW- I HATE going DDW because apparent wind won't get the heat away!).

cup

then drop the dodger ... lol....for ddw!!!~~~~~~_/)~~~~~.

Dan Johnson · Jul 30, 2009

Stu...

I was holding out for a bribe, but since you so boldly insist...

I can't remember what the label says as the stuff is down on the boat. However, the WM store receipt says it's "Protectant - H2OPRF Tf" with a WM part # of 10174779--wait a minute...let me go fetch the catalog...

It's from Pure Oceans and called NanoTec Waterproofing Protectant. Comes in a 16 oz spray bottle for $16.99. It's waterbased with no distillates and claims to work at the molecular level to create a waterproof barrier. You can get a gallon for fifty bucks for circus tent protection-sized jobs.

I'm going to be testing Starbrite's Spider Away and their Spider Stain Remover shortly.

Bad Obsession · Jul 30, 2009

I have royal blue for my bimini and dodger. I can feel the heat beating off of it in a hot day but when underway it isn't as bad. That being said, I believe that the area would still be hot no matter what the color is when the sun is beaming down on it. Also, considering that the other option of having a naked cockpit, the color of the dodger and bimini is not a big consideration when considering how much cooler it is in the shade.

Let's face it, no matter what your bimini color or any of those factors, when going dead down wind it is just brutal hot. Thank God for the shade because without it heat stroke would be a distinct possibility.

Stu Jackson · Jul 30, 2009

Thanks so much, Don

what kinda beer d'ya like?

Dan Johnson · Jul 30, 2009

Stu...

You guys ever heard of Rolling Rock out there? I could make do with an Anchor Steam pilsner in a pinch...:dance:

Stu Jackson · Jul 30, 2009

I went to Penn State. They still making Rolling Rock? In those small green tiny bottles? And Anchor Steam is not, as I understand it, a pilsner...it's a tad "heavier"...

Dan Johnson · Jul 31, 2009

Yea, Stu...

they're still making RR in little green bottles and cans as well as 12 oz ones too! A-B bought them last year and now there's rumors of their pending disappearance. For "heavier" suds we turn to Yuengling Lager or its Black & Tan.

I recall having had a light colored Anchor last time I was in the Bay area--thought they were now making a variety of specialty brews.

Just was up PS campus for daughter's MFA art show on campus--you wouldn't recognize it from only a decade ago.

Bill Roosa · Jul 31, 2009

Dark colors in the winter

Us northerners have long known the benefits of darker colors in the winter.
My navy blue full enclosure extends my sailing to mid Nov or early Dec and I can get back in the water in March when the ice leaves.
If it is 32 out before dawn, the temp will get to 50 within an hour of the sun coming up. Course it cools down just as fast when the clouds come out.