Cruising with Camper Canvas

Gettin' There II

Gettin' There II

New Member
Apr 1, 2007
67
Navarre, FL
Boat Info
2007 240 DA
Engines
5.0/Bravo III
We are now cruising on the Florida Panhandle with our camper canvas on. I remove the rear portions of the canvas before we launch and also remove the front center piece over the walkthrough, however I have noticed a lot of the station wagon effect while travelling at speed.
Would I be better off by leaving the rear portions on? Of course removing other sections to give proper ventilation. How about leaving the front and rear closed but opening the sides? Any thoughts on this?
I did read the other posts on this but still can't make up my mind on the best practice.
Thanks
 
It depends on the winds. The only real way to tell is to carry a digital readout CO monitor/detector. Assuming your forward motion negates any prevailing wind (not always a good assumption), your configuration should be fine, so long as you back it up with a CO detector.

We run our 340 with most of the canvas up, sometimes all. We open the small vent window for fresh air and to control the temp inside. Even in winter, if the sun is out, it gets hot inside. You may be better off with the aft portion up, so long as there is a way for the air to escape to keep the airflow coming. I wouldn't shut them all (front and back), though.

Bottom line: CO is odorless and tasteless. Engine exhaust is not, but you get used to the smell. If you don't have a CO detector with you in the cockpit, keep fresh air blowing over your face. People in the cabin (if available) are not safe. Use a CO detector.
 
Great advice from Hampton...my CO detector in the mid-cabin goes off in about 2 minutes with canvas up at slower speeds.
 
In my Mercruiser Manuel it shows the cabin hatch open when under way to help prevent this.
 
When I had my 240DA I had everything up, except front center piece. This would be similar to what John (Hampton) was describing. The only issue was at cruising speed is that clips (they were holding the bottom of the curtain) for the back curtain would not hold, due to mass airflow, and unclip. But, in a way it was good b/c this had created good ventilation. If it gets too cold I would only have very small part of the center curtain open. That worked fine.

As for CO detector, you can simply get one 9v (battery operated) from Home Depot or any hardware store, they work just fine and cost only few bucks.
 
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Where do you guys mount the detectors? And what do you use? I'm thinking I could mount it on top of the rear-facing bench seats behind the helm, but I don't want to use adhesive that will mark up the material.

-T
 
Gettin' There II said:
Thanks for the feedback, anyone have a handheld CO2 unit they can recommend.
Click to expand...

http://www.detectcarbonmonoxide.com/about.html

Just got it today. this is my solution for monitoring in the cockpit and using as a backup in the cabin at night.

Cannot say that I can recommended as it has not saved a life...yet.

The manufacturer of these seems to be a quite reputable builder of gas detector systems, so why not.

It is small enough to go anywhere and is about the size of my Car key. Nice readout and memory options look great/Min/Max exposure,etc.
 
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I guess, one of the options is to use velcro (no holes and hold just fine) and mount it in the helm compartment right under the shifter by the captain's cup holder. I don't know what's the proper name for it, but I'm sure you know what I mean. Also, you can just mount it behind captain's chair next to the fire extinguisher.
 
CO is heavier than the normal atmosphere, which is why it will settle in the cabin if the companionway door is open while you are underway and in conditions that allow CO into the cockpit. In the winter, if we are cruising with the camper canvas on, we'll have the winshield vent and the forward foredeck hatch open to catch fresh air, and the bottom of the rear side curtains unsnapped to exhaust it. Opening the sliding window above the mid-cabin berth a bit after we get going exhausts the cabin air into the cockpit.

I like the idea of the portable CO detector; that's now at the top of my boat shopping list. I'll put it in the rear of the cockpit if anyone is sitting there, since they will be lower than those sitting at or beside the helm, otherwise it will go next to me at the helm.
 
I keep a couple of the battery operated ones in a drawer. When we cruise, I set them in the cockpit. When we sleep, I place them near us in the cabin. I don't mount them anywhere.
 
My boat has underwater exhausts - I don't know if that cuts down on the amount of CO that makes its way into the cockpit or not. Does anybody have any light they can shed?

-T
 
While CO may be heavier than air, it's still lighter than water, and will float to the surface, as will all exhaust gases, although a small fraction may dissolve into the water on the way.
 
tmhudson2 said:
CO is heavier than the normal atmosphere, which is why it will settle in the cabin if the companionway door is open while you are underway and in conditions that allow CO into the cockpit. In the winter, if we are cruising with the camper canvas on, we'll have the winshield vent and the forward foredeck hatch open to catch fresh air, and the bottom of the rear side curtains unsnapped to exhaust it. Opening the sliding window above the mid-cabin berth a bit after we get going exhausts the cabin air into the cockpit.

I like the idea of the portable CO detector; that's now at the top of my boat shopping list. I'll put it in the rear of the cockpit if anyone is sitting there, since they will be lower than those sitting at or beside the helm, otherwise it will go next to me at the helm.
Click to expand...

:smt021 First I'll beat the sh-t out of myself and save everyone else the trouble. I don't think CO is heavier, what I find is that it is slightly lighter but so close as to be generally considered the same weight so I don't think it settles for example like we would think of gasoline vapors settling. CO actually mixes with air easily. I believe Co entering a cabin under the conditions you describe...underway, cabin door open...are the result of air movement in and around the boat. Specifically the station wagon affect.
 
I understand CO to be the same weight as air. When it's warm compared to air, it rises. This would be the case after being a by-product of a small explosion in an engine. Underwater exhaust does help. I think your boat has underwater exhaust for cruising, but side exhausts for idling. I believe the side exhaust is always open. At idle, the exhaust does not overcome the water pressure, so it vents out the side. As you increase fuel consumption, it over-powers the side exhaust's capabilities and, using the excess pressure of a revved up engine, blasts the remaining exhaust out the bottom.

The exhaust out the bottom rises to the surface at a greater distance behind the boat, thus making that portion of the CO much less of a factor. If you are in a tail wind slightly greater than your forward speed, all of these gases can affect you. If your boat is in perfect running order, I would not expect the gases to be much of a problem at cruise. At idle, or with a potential exhaust leak, the gases become deadly. A CO detector is a great asset unless you're crusing along with fresh wind in your hair.
 
I stand corrected. I looked up the specific volumes of each; at normal atmospheric pressure and 77F, air is 13.5cf/lb., and CO is 14.0cf/lb.
 
Hampton said:
I keep a couple of the battery operated ones in a drawer. When we cruise, I set them in the cockpit. When we sleep, I place them near us in the cabin. I don't mount them anywhere.
Click to expand...

+1 for us too and I just bought a replacment one from BOE for the OEM (even tho it seemed to work fine)
 
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