Raising boat from trailer for bottom painting

My catalina 25 is on a trailer and am going to bottom paint. Need to raise it up about 10 inches to paint under post pads, under the keel, and place where the side of the keel is behind some wood to keep it centered on the trailer. I was going to use some padding with plywood and then a piece of sheet steel above a jack in the centre of the boat where the sling lifting marks are. Would the be good to avoid damage to lifting the hull. or is there a better way to lift it 10 inches

Do you really have to lift it that far to slide a brush loaded with antifouling between the pads and the hull? Even the bottom of the keel would just need a 2" space to get a brush in there. You could probably get that by lifting the bow first, lowering it back down, and then doing the stern. If the wood centering piece is in the way can you remove it and replace it afterwards?

I can’t claim to be any expert, but I get a lot done myself.

PSK125 has a good answer, then add the single pad lowering for the rest of the job.

  1. Use front pads to raise bottom of front of keel, paint there,
  2. Spend some time painting the rest of the hull while bottom front dries,
  3. Lower when you figure the keel is dry enough,
  4. Use rear pads to raise back edge of keel, paint there,
  5. Spend some time painting the rest of the hull while it dries,
  6. Lower only one pad a few inches to paint under that missed spot, repeat for all pads

This boat has a fin keel so the bottom of the keel is about 24x18 inches and then 6 pads at 12x12 inches. to reach under the keel I would have to raise it at least 5 or 6 inches.
not sure I how to use the “front pads or back pads to raise the” boat. Do you have an idea how to raise it safely if I do not have a sling to surround the boat.

If you could post a picture we might be able to understand the problem better. It is usually quite simple to lift the bow of a boat on a trailer up by using a car jack with a wooden chock and a cushion under the stem area. This should lift it enough above any forward trailer pads to get a brush of antifouling there, while the stern pads hold it steady. When that’s dry, the same technique will work with the stern.

photo shows the wing keel that I need to paint under and above that is one of the 6 one square foot pads. There is also a 2x6 where the keel meets the hull. I was thinking of raising the boat where the bricks are piled but I jacked it up an inch or so, it did not move the keel so I quit that thinking I might do damage to the hull. on the hull between the dark and light blue is the sling marks. So I still have to lift it about 8 inch or wait until I go to a marina with a lift and paint it then.

The picture does clarify things. Those 2x6’s are pesky. They’re probably helpful for centering if you’re retrieving on a ramp, but certainly in the way now. Are they bolted on so that they could be unmounted? Otherwise, slapping some paint on in the slings is better than nothing.

If the marina puts the boat back in the water, they will usually do this for you if you leave the paint and a paint brush.