Hi Seadog,

I'm assuming that the 100mm clearance is without the trailer underneath

Back in SA we used to used large rubber sausages (can't remember their real name) to move the boat up and down the beach to launch and retrieve.  What you could try (if you can get hold of a couple of similar items) is using a winch (or cable off a snatch point), the sausages and a couple of mates is something like this:

1. position (if you can) all but 1 sausage under the boat
2. position the remaining sausage in front of the boat so when it rolls forward it will move onto the sausage without hitting the ground
3. remove the timber packing
4. pull the boat forward using car or winch moving the sausages from the stern to bow

This should get you out the shed then you can manoeuvre the boat onto the trailer.

I think there was once a thread that talked about beach launching in Northern WA - have a look at these --> http://www.praktek.com/mcart/index.cgi?code=3&cat=8

Alternative - much like letting the tires down on the truck stuck under the bridge ..... I'm guessing a reasonable sized shed.  Any chance you can easily remove any of the pannels to provide more height?

Good luck

Having just had a look at FishOn570's post on his new tub - see if you can borrow a dolly similar to what's sitting under the  680 in the pics posted.  Not sure how you'd get it past the timber packing though ..... where there's a will there's a way!

 Or a contractor with a big forklift like at the boat lifters...

How high is the packing under the keel?

Is the floor of the shed concreted.

Do you have a trailer for it?

The reason I ask is, if the wheels of the trailer were removed, and you put some industrial "Skates" under the axle, would there then be "roof clearance" when pulling the boat out?

I know of special boat jacks that will lift the boat up, so the keel is clear and a trailer or some frame could be slid in under it..