Boat tent specs?

[jsjpd1]

Hi everyone,

Awhile back there was a thread on open boat camp cruisers that talked alittle bit about boat tents for overnight accomodations. This led me to want to do something similar for my open boat. I have a 19' 6" caldonia yawl with around 10' of cockpit space that I'd like to design a tent over. I have plenty of tent fabric and five dome tent poles, three ten footers and two 14 footers. My idea is to run the 10 ft poles across like hoops in a wagon top, one in the middle and one on each end, then run the long ones diagnolly through the mid section of the tent. I think it would look something like this.

http://i646.photobucket.com/albums/uu186/jsjpd1/sparrowtentidea.jpg

http://i646.photobucket.com/albums/uu186/jsjpd1/Tentpolelayout.jpg

Does this seem like a reasonable idea? There was some discussion of windage being an issue. How tall would you make a tent like this? Based on the thwart hieght of my boat, I was thinking that some where in the 3.5 to 4 foot range would be about right for hieght from gunwhale to ridge line. What do you think?

Jim

[Thorne]

Here's a few things I've discovered when playing around with tent poles, covers and boats:

1. Many fiberglass tent poles are designed for a specific max bending angle. Exceed that and they fail -- either sooner or later but they'll always fail. You can shorten or lengthen poles, to shorten pull the elastic cord from the center, trim the ends, sand same (NASTY fiberglass dust!), then restring the elastic with a thin wire -- but again some poles will crack and split if shortened even as much as 15%.

2. One uber-simple solution is to buy an existing (but inexpensive) tent with the same dimensions as the area you want to cover. Cut the bottom out, leaving flaps on the sides and ends for extra protection or moisture barriers. VOILA! For some boats, a child's tent will work. For others you'll want something larger -- but the doors must be on the ends which is rare in modern tent design.

3. There is a good reason why good tents have a breathable fabric "tent" and coated "fly" -- the alternative can be very damp in many camping conditions. If you do go for a single waterproof layer, factor in the drip and smear issues to keep the fly away from your head and shoulders, and from dripping on bedding.

There have been some good threads on this topic here -- worth a search.

[Ian McColgin]

I've built quite a few various boat and cockpit covers. In my experience it's easier to make something right from a bolt of fabric than it is to modify a tent to fit.

The hoop idea is great. The diagonals will not really help. Were I building this with what you have at hand - this presupposes that your three shorter wands will take the bend, would be first to see if the two longer wands will also take the bend and thus be available for cutting down.

Five arches would be rather nice for a number of reasons, one of which is that you're likely to end up with a long enough tent and enough room in the seam layout to make the hoop tunnels in the seams.

I'd go about designing it by errecting the hoops on the boat. You'll find, given the shape of the gunnel, that the hoops are different sizes. In the end, you'll be doing some cutting.

Before cutting the arches, consider how they will land. If you have an inwhale seperated from the gunnel by the frames, you could make landings for the hoops in that space. Alternativly, you may have some wee blocks inside the gunnel that have holes aimed to recieve the arches. Essentially, snap in place.

You'll want to keep water from running down inside. I recommend having he hoops emerge from their hem tunnels an inch or two short of the gunnel and have a grommet on the inside half of the tunnel, in the hem there, so a light line can tension the cover over the hoop. Have the outer and finished hem long enough that is lays over the gunnel. If that hem is three or four layers thick, it will be heavy enough to lie over the gunnel.

Fiddle with a number of ways to do this before you start cutting wands and fabric.

Once you have the plan, set up the hoops on the boat. Guy them in place and then make some fore and aft as well as diagonal connections between the hoops. Dacron (or some not stretchy) twine and tape will help here. The goal is that you have a stringy structure that you can lift on and off the boat, thus transferring the real shape from the 3-D shape on the boat to a more or less flat thing when laid on a large enough floor.

If you're lucky and plan well, you'll end up with four panels and enough space given the fabric width for a good cover. Maybe even too much, and you go to three panels and four hoops.

As you lay it out, you may find that only the center panel(s) can go all the way across in one go. This is because the fabric must be exactly normal to the outer hem. If you rely on the hem, even a liften hem, to hold the shape you'll end up with sagging between the hoops. So where the boat is narrowing, the shape between arches becomes a shallow V. If you plan that and connect the two sides of each panel with it's center seam before joining the panels together you'll end up with panels where the overlap of the joining seams - which are also the wand tunnels widen slightly in the center. This is fine. Visually attractive and the wands will find their way.

The center fore and aft guys are easiest attached if you modify the hem at the center such that the wand is exposed for a couple of inches there. That way you can tie to the wands. A grommet there tends to bunch the fabric unattractivly. It's convenient as you have the center line seam joining the halves right there anyway.

G'luck

[kenjamin]

A picture may be worth a thousand words. Here's Dale Davenport's tent on his CY:

http://ford.physics.fsu.edu/DaleDavenportBoat.jpg

Check out the Caledonia Yawl website to get in touch with Dale and to register Sparrow, if you would like.

http://www.mavc2002.com/caledoniayawl/index.html

Personally, I think the diagonals will add wind resistance to the tent. That's why dome tents use them.

[jsjpd1]

Thank you gentlemen, you've all given me alot to think about.

Jim

[John Turpin]

I'll be using my Lapwing for a couple of week-long camp cruises each year. Those places aren't always conducive to pitching a tent and I like keeping everything in the boat anyway. I'll be adapting the bimini enclosure below to my cockpit. This will let me "wall in" the cockpit and give me a certain amount of shelter from the elements (but not bugs unless I somehow encorporate mosquito netting). I picked up the bimini and enclosure for about $200.

http://www.boatstogo.com/images/Canopy/Tent_Canopy/Canopy_Tent_Test/Canopy_Tent_Test4.jpg

[WI-Tom]

You might want to check out Darroch's tent for his Kurylko Alaska; it seems to be much like what you planned--he has a thread called "beach cruiser Alaska" on the forum--look for post #67 and following.

Tom