I have too many boats and not enough space. Sound familiar? Here is what I came up with to help me out. This is a Michalak Mayfly 14, but should be applicable to many others as well.
I started out by making the “L”s right on the boat so I knew they would fit size and angle wise. I added some “filler” 1×3’s and notches so the chine log as well as the sides of the boat would be weight bearing. Your hull might vary. Here is a detail of that:
(And yes, I did fix that gap on the right side swivel roller 2×4 mount later on!)
I let the 1×3’s on the sides of the hull lay flat to the hull which gave the longer portions of the “L”s an angle off vertical as shown below: easier than cutting all those angles.
I laid the hull down on the properly spaced and horizontal laying “L”s and added the 2×4 roller mount beams to the short side of the “L”s. Then levered the hull up on its side to find a good balance point for stable rolling. (No rollers yet though.) In this case it was just fine so I did not have to add any sub-frame to get a good angle/position. I added the top cross piece and two short handles for ease of levering up and finger clearance to the ground, as shown above. I noticed the the full weight of the hull came onto the rollers at a sideways angle while rotating up into the storage position, and though they are rated at 180 lbs each, I figured that sideways force might be too much. So I added a short Pivot 2×4 to rotate up upon till the rollers were almost vertical. Detail below. It works just fine.
I load the boat from the position shown below. For one man, lift and prop the bow, then the stern, to get clearance for the long side of the “L”s. Then slide the cradle under the hull. Remove the props and check the position of boat to cradle. Then lever it up with the handles on the Pivot 2×4 to the rolling storage position.
I added some green padding to the cradle and it is done. Some 2X4s, short 1x3s (could be 1x4s as well), and assembled with 2 1/2″ deck screws and some wood glue. I got two swiveling rollers and 2 straight rollers for maneuverability. Steers like a dream (or grocery cart, at least!).
It works really well. Maybe two hours, <$25 worth of rollers, and in my case some left over wood. I will be able to snug this into the side of the metal carport for storage, be able to pull it out and back in when I need the room, and get to it when the weather and owner (son in law Pedro) are available for sailing!