Hatch covers and boom tent

[Ded reckoner]

We have a white hull with navy blue trim and the Sunbrella UV protective parts of our main and headsail are navy blue. We like the contrast, so we have made our hatch covers navy blue. The pilothouse windows and hatches have a tinted film on them to keep out 50% of incident radiation, 97% of IR (3M Crystalline CR70). Texas and Florida are still too hot in the summer for just this film, so we block incident sunlight on the windows and hatches with form cut double sided Reflectix insulation from Home Depot (i.e. air bubble insulation with double sided aluminum reflecting film). The hatch covers are on top of the Reflectix. Today, we took one hatch and changed the hatch cover from navy blue to off-white canvas. We used an IR temperature gun and measured the inside temperature of the center of the hatch compared to an adjacent hatch with a navy blue cover. There was about a 10 degree F difference in temperature with white being cooler. This was reproducible over time. Then, the covers were switched for those two hatches. The temperature difference moved with the changed hatch covers. Of course, everyone knows darker colors will be hotter than white, but here's our little experimental result. We will transition our hatch covers to off-white and the same for the boom tent.