The ridge prevents low spots that allow water to pool. This is vital for outdoor storage to prevent the water from oozing through breathable cloth (which is necessary to prevent rot). Since you're storing indoors, you don't need a ridgepole for that.

If you will never be driving through rain, or staying overnight somewhere that the boat has to stay out in rain, you don't need the ridgepole.

But if you end up driving through a thunderstorm, the lowest part of the cover will fill with water, get heavier, get deeper and fill some more. If that's a breathable cover it will drip into the boat. Your trailer load will get heavier, regardless of the fabric type. The load could get unstable as the water sloshes, either in the cover or the boat. Heavy, unstable load while driving through a storm (in the hills on I70) - hmmm. Ridgepoles are your friends.

Or you can travel only during droughts :-)

Be safe,

Laszlo

   I see no reason to have a cover if you are storing it in the garage.  As for towing with the cover on I think you will find that more trouble than it is worth to try and fit a cover that stays on while at highway speeds. I am curious why you think you need a cover for the short trip to MD.  I suspect you are going to Deep Creek Lake? 

BTW what part of the 'burgh' are you from?

   Thanks for your insights! Laszlo, you're right... now that I think about some of the weather we've driven through, the last thing we want is an unstable load. We drilled for the bow sockets yesterday. 

We'll be trailering her between Pittsburgh and Kent Narrows (outside Annapolis), which is a longer haul than Deep Creek. I ended up doing quite a bit of veneer work and some marquetry, so I don't want to travel with her uncovered. (She got a little dinged up on the drive back to Pgh after our build class at the Annapolis CLC). We will also eventually be towing her behind a larger Island Packet, which we will need a cover (with a ridgepole) for.

Oceanluvr, I grew up in the South Hills but have lived in the all over the city for the past 20 years. Right now we are settled downtown. Are you from out this way?

   I have a line with a loop that goes over the bow. I drop a 1x3 that has a short piece of pvc pipe  with a slot cut in attached to one end into the dagerboard slot.  The line lays into the slot and runs to the stern.  At the stern, the line is tied to a 6" piece of pvc pipe that spans the sculling recess.  By adjusting the height of the dagerboard 1x3, you control the slope to the sides.  Since adding this setup I haven't had any pooling on the cover.   Barry

   I am with Oceanluvr on this one.  No need for a cover unless you are storing the boat outside.  Lesson learned from 34 years of trailer sailing is to never trailer with any canvas on.  When (not if) a bit of the canvas comes loose, it will beat itself to death in a very short time at highway speeds. The flailing death is usually accompanied by cosmetic damage on the boat.  For my money, I always trailer with the boat naked.  If the boat is upright, your best bet is to install a drain.  IMHO, a boat the size of a NE Dory needs a drain anyway.  Without a drain, it is difficult to de-water the boat when (not if) the cover comes loose in a heavy rainstorm.  A drain also makes it easy to rinse all the salt and sand out of the boat.  I am installing a pair of Anderson Bailers on the 15' skiff that I am building.