need help with car top tent replacement fly design

[semlin]

one excursion into the beautiful bc rainforest has established the car top tent must have a new fly to be useful for me here. So i need some suggestions on how to design a new fly for my mombasa car top tent.

I'm meeting with a boat canvas guy this coming weekend to get some canvas on my boat repaired. He has agreed to look at making a fly for the tent. He is slow over the winter so if this works out he would be able to make them to order for those who want them. in fact, if he gets a bunch of orders the price might come down for everyone, so i may try to organize a group buy

anyway, first things first, the design...

we are talking about making it out of mid-grade industrial tarp material, but am open to suggestions on cheap durable waterproof fabric..

I want the design to keep as much rain as possible off the tent. I do not trust the tent's base to keep water out if the sides get soaked.

SIDES

My current thought for the sides (including the entrance) is a centre awning something similar to the technitop pictured below (thanks to dieseldan for photo), but instead of using a tent pole from below, use either

(a) a collapsible shock cord tent pole that fits into pockets and loops sewn into the bottom of the tarp, similar to the ones used on regular tents as in the top left hand corner of the second photo below. This would give a rounded umbrella shape.

(b) three rigid tent poles that fit into pockets under the tarps. One long pole and two short ones that would follow the ridge line of the tent.

Not sure which would give better weather protection. Either one would have corner tie downs plus snaps on straps that would utilize the snaps that hold the existing fly in place.

ENDS

For the ends, I am thinking of running a square tarp straight off the end that is the same width and just a little longer than the tent wall. This way you would have the option of leaving it rolled up, or letting it lie against the tent and tieing it at the bottom, or adding two poles and making it into an awning.

The only problem with this is I don't know how to ensure that water does not run off the edges and down the four corners of the tent.

Anyway, let's have your suggestions on how to do it, and do it simply, plus any interest in the group buy idea.

 

[e9999]

good idea

seems like it would be easy too to screw brackets for poles etc to the aluminium frame of the CTT.

I'm thinking that using just the existing snaps will not be enough to hold the bigger fly in case of serious winds. Needs something else.

 

[Shahram]

My concerns for the design would be weight and any subsequent stress it would put on the tent. We've already established that this tent isn't made bulletproof. Anything that might increase stress due to wind profile, added weight, etc. would be a concern for me. I'd try and go with the lightest material possible and simple--just cover the tent and secure down.

 

[Montana Cruiser]

I am certainly interested in a group buy as I have already learned this tent NEEDS a better rainfly. I am planning on unfolding the tent in the garage tomorrow and trying to come up with a plan, will get back to you.

 

[REZARF]

Good thread, I am exploring this myself.

The ladder and the fly both need work.

I like the idea of the awnings on each side of the tent that has a window. However, with the overall size of the CTT I would suggest adding two poles (shock cord kind, though it wouldn't matter if they could break down with the space available to store them).

I would attach the two poles to the base below the widest point of the window's and door. Then allow them to slide into a "sleeve or pocket" in the fly at a point that is just as wide above the door and windows. Then I woud create a tie down system at each bottom corner that would allow you to tighten or loosen according to the conditions. I would see each "awning" extending at least 18" from the tent if not 24" I would have to see it to know how far out you should go.

Clear as mud?

Keep us posted, I would be interested in a group buy.

Rezarf <><

 

[semlin]

rezarf not sure i get you. are you saying a big square with crossed flexible poles. basically a big square umbrella with the corners aligned over the entrances? It would be cheap to sew but a bit of a wind trap. I'll add it to the options to discuss. He said the material would be cheaper than the labour.

 

[brittan]

I spent 5 wet days in the tent while on a trip to Moab. During the night I would wake up to push on the top of the tent where water had collected. I am not as concerned about the sides as I am about the top. If I didn't live in AZ I'd dump the tent. Like Shahram I am concerned about weight...

 

[semlin]

I spent 5 wet days in the tent while on a trip to Moab. During the night I would wake up to push on the top of the tent where water had collected. I am not as concerned about the sides as I am about the top. If I didn't live in AZ I'd dump the tent. Like Shahram I am concerned about weight...

brittan, where exactly did the water collect?

if that's the case, maybe the rezarf idea makes sense. if the fly has crossed bent poles to acts as battens to stiffen it and shape it into a dome, then water can't collect anywhere.

Two fibreglass poles and a piece of tarp won't add any meaningful weight. the issue to me is whether wind will get underneath it like a sail. I've rigged plenty of overhead tarps and never had one blow out so i'm not sure if that is an issue.

 

[brittan]

The water collected in the trough between the center support pole and the side support poles. I couldn't tighten the adjustment straps enough to stop the water from pooling. Moab had record rain in early Oct of this year and I was in the middle of it. I ended up in a hotel for the final night of the trip...I just wanted to be dry. I do think it's a good tent for what I paid but in my opinion it is a two season tent. Attaching a canvas tarp may cause more issues...if there was a way to place support poles inside the tent for extreme weather I'd be for it.

 

[semlin]

thanks, so you are saying the tension cord in the tent would not cynch up enough to keep the canvas taught? If the fly held up otherwise you could fix it by putting poles/battens into the existing fly.

a couple more quick questions about your field test

-how did the sides and bottom of the tent hold up? did the mattress get wet?
-how windy was it?

 

[brittan]

No wind to speak of...the sides of the tent held up well. It was the top that had issues. The mattress did get wet and when it did it lost all of its spring characteristics. It was not a pleasurable experience.
I met another mud member up there who had the same tent. Ironically we were both at the same hotel for the night. He was worse off than me. He didn't have a rubberized cover for his tent...I did. His was wet from day one. He had a canvas or nylon cover, I don't remember.

 

[lx450landcruiser]

If any of you want pics of the ezzi awn set up id be happy to take some pics. i used it the first time in the rain last weekend. started pouring at 3 am and never stoped. i left an empty can on the hood of the truck that night and when i woke up it was 4 inches deep. never got wet though, like sleeping in a cabin. the design is very simple and could be easily duplicated.

mike

 

[semlin]

mike, a photo would be great.

 

[dieseldan]

I was speaking with my buddy who does most of our boat tops where I work. He had a good suggestion that could be adapted to nearly any RTT.

If you made up a framework of alumimun square or round tube (square tubing with square plastic connections are less expensive) and built an exterior framework that could be easily assembled and stored inside the collapsed tent, you could easily cover this with a tarp - or have a slip cover made for it.

The mount points would be sleeves attatched to the RTT base at each corner.

He drew it out on paper and it looks simple, cheap and effective. Of course you can beef it up depending on what function is most important.

 

[Montana Cruiser]

I was speaking with my buddy who does most of our boat tops where I work. He had a good suggestion that could be adapted to nearly any RTT.

If you made up a framework of alumimun square or round tube (square tubing with square plastic connections are less expensive) and built an exterior framework that could be easily assembled and stored inside the collapsed tent, you could easily cover this with a tarp - or have a slip cover made for it.

The mount points would be sleeves attatched to the RTT base at each corner.

He drew it out on paper and it looks simple, cheap and effective. Of course you can beef it up depending on what function is most important.

After looking at mine for awhile yesterday, I have to agree, it needs SOME sort of framework for the rainfly. I don't think simply adding onto or enlarging the current fly is going to do much good.

My thought was simply and "X" framework of two collasable tent poles with an attachment in the middle of the X to hold it in place and then bungee or some sort of cord pulling each corner back toward the base of the CTT. Obviously the fly would be much larger then the tent itself providing some eves for the tent. If it was raining, You could assemble the fly before pulling the CTT open, pop the ten open and hurry and set the fly up there. I would also leave the current fly in its place for any added barrier it could provide.

 

[semlin]

i am increasingly thinking crossed poles and a simple square is the best plan too. i am meeting the guy tomorrow and i will discuss dan's collapsible frame idea as well. my guess is the original full featured fly would be too much...

if anyone knows where to source those fibreglass shock corded tent poles let me know.

 

[dieseldan]

Hey Semlin I have a bucket of poles you can likely use it you want to experiment. A buddy sold me a swiss army tent that I could park my cruiser in - never going to use it and he gave me a pile of collapsable poles with shock cord. Many of these are closer to 3/8th and beefier than the usual dome tent tensile strength.

I can drop em' at Greyhound if you want em. I'll take a photo over the weekend.

 

[e9999]

guys, don't underestimate the force needed to hold down an 8x8 piece of tarp in a strong wind....

 

[lx450landcruiser]

arnt most of you using yakama bars to hold these tents on? what if you got some aluminum pipe and have it bent in to large square hoops. pop rivit the hoops together in the middle so they hinge, then you slip the pipe over the ends of the yakama bars and they make another frame work over the tent you just throw a tarp over the hoops and snap them down to those snap rivits you can buy. that would mean you dotn need any tools or fasteners.

 

[Montana Cruiser]

arnt most of you using yakama bars to hold these tents on? what if you got some aluminum pipe and have it bent in to large square hoops. pop rivit the hoops together in the middle so they hinge, then you slip the pipe over the ends of the yakama bars and they make another frame work over the tent you just throw a tarp over the hoops and snap them down to those snap rivits you can buy. that would mean you dotn need any tools or fasteners.

Now thats a really great idea Mike! Just need to figure a way to keep the "hoops" steady, or were you thinking the fly would do that once the tension was on there?

Edit: I'd still really like to see the set up for your CTT sometime too