Black boats in the sun - Car topping

I’ll be heading to the west coast for a trip next month and along the way will be picking up a Bell Northstar in Black Gold. This got me to wondering if I need to be concerned about heat build up in the hull while it’s on top of the vehicle.

Not too worried about when I’m actually driving as the air flow should keep it cool but it could reach triple digits in places along the way and I wonder what would happen if I were to park the vehicle in the sun for a few hours in such weather.

Obviously I’ll try not to park in the sun but it can’t always be avoided. Should I be concerned about the hull?



– Last Updated: Jun-24-14 9:19 AM EST –

nothing is going to melt.

I have a RapidFire in carbon fiber and its dark. Its been cartopped to FL many times.

I don't even worry about our Kevlar canoe which has now been back and forth to Utah twice.

Long term storage is a different matter if you have lots of sun exposure. On our two week canoe trips in the desert we don't cover our Kevlar canoe either while on the river after the days paddling is done. I haven't seen anyone who does.

If you get a bag, get a good bag made for the specific boat. That will avoid flappage. I use bags by the Bag Lady. Boats transported in the winter are always bagged to avoid dings from sand gravel and flung rocks from snow removal equipment.

If it was me, I would get a cover…
for it. A light color one or silver.

I don’t know about that boat, but if it has a clear coat I would think the sun will hurt it.

I learned a long time ago to cover our Kevlar Jensen when we are in Florida for the four winter months.

Over a long exposure it will start to degrade then peel. I used to constantly have to redo here and there until we got a cover for it.

jack L

sun kills
Plastic boats will warp under high temps, and ive had composite/glass boats melt/become cosmetically damaged.

Put em in a big white sock.


Good to hear
Wasn’t really concerned about melting but didn’t know at what temperature it could start to affect the laminate. I probably won’t worry about a cover since, at this point, the boat won’t normally be doing a lot of traveling.


I’d like to see some photographic
evidence of sun/heat damage to composite boats. I’ve been trucking around epoxy S-glass/Kevlar and vinylester S-glass/Kevlar canoes, all over the hot west, and I have never seen any damage whatsoever.

Hmm, Me Too

– Last Updated: Jun-24-14 10:09 AM EST –

Having a black Esquif Mistral and Blackgold Starfire (Same layup as your Bell) in lots of 90-100 degree summers. The black vinyl of the Mistral's gunwales get hot, but the black carbon/polyethylene hull does not feel uncomfortably hot

Don’t even attempt transpot of a black

gold Northstar, unless bringing it to me. Could be very dangerous, otherwise.

Seriously, I’m envious of the Northstar and don’t worry about the sun during transport. Use som 303 before the return trip, if it all ease your concerns.

I’ve been looking for a Northstar with aluminum gunwales.

are you up to your second garage?


– Last Updated: Jun-24-14 10:47 AM EST –

There are hundreds of thousands of dark-colored powerboats of composite construction in this country, and the more they get used, the more their top surfaces are out in the sun, supposedly "cooking". Plenty of them are no longer used, and just sitting in backyards too. If the material in the upward-facing parts of these boats were getting damaged or "melting", the problem would be well known, and black wouldn't be one of the more popular colors right now.

Sounds like this is your boat then, complete with aluminum gunwales. I’ll do you a favor and not tell you the price. :slight_smile:


I have a composite carbon blade kayak
paddle that, if it is inside the car and the sun hits it, the paddle will swell up inside. I think the design involved layers of prepreg carbon. The builder replaced it once for me, and after that I’m just careful to keep the blade in the shade.

I say this just to note that sun and heat exposure to carbon laminate can cause softening. But it would seem that it does not occur with thin hulls.

I need to sell some boats. I need someone to buy the kevlar Shadow 16.5. …and a few others…if I can decide which to sacrifice.

I appreciate your concern for my
feelings. You now know an option for unloading it, if it doesn’t blow your skirt up…at a similar undisclosed price :slight_smile:

My carbon paddles live in my trunk
much of the year. No obvious ill effects, so far.

It isn’t just heat, it’s what happens
when a black paddle blade is sitting in the sun and that radiant heat just pours in.

My Epic carbon has a milky clear coat.
I bought it that way and my understanding is that the original buyer bought it as a factory 2nd with some milkiness already there, so I don’t know how much, if any, was cause by UV from the sun. He kept it bagged much if the time.

In hindsight, this post probably doesn’t contribute much to this discussion. Oh, well.

I still don’t leave this boat on the car rack for weeks at a time like I will the others without the clear gel.

There’s no difference between heat and radiant heat. My guess is that your paddle has some internal foam or some other layer with a small bit of residual moisture in it. When it gets overly hot, you may be getting an internal pressure increase and hence some swelling from high temp water vapor.

The difference is that ambient heat,
the heat inside the car, heats the paddle blade by conduction.

But if the paddle blade happens to also be sitting square in the path of the sun, then heating of the blade also occurs through infrared and other frequencies.

When you’re barbecuing in your back yard, you can reflect on these matters. Think how your steak is cooked by radiation as well as by conduction.

You were talking to an engineer and …

– Last Updated: Jun-24-14 5:55 PM EST –

... he noted that you used the inappropriate terms. More clear would have been to differentiate between ambient temperature and the higher temperature of the paddle which could result due to direct exposure to sunlight. The amount of "heat" in the trunk doesn't tell you anything at all about its inside temperature, in much the same way as a gallon of lukewarm water contains far more heat than a red-hot nail. To relate heat to temperature you need to know what volume of material it's packed into, as well as the specific heat of that material. There might be more to it than that even - I'm sure the balance between radiative heat absorption and radiative heat loss gets complicated. I understand your point though, in spite of the wrong words.