I know this subject has been on here before, but I thought I'd throw this into the pot:
I have an Oday 25 that sits on a bomber homemade trailer - made by a welder. Its one big problem is that because he didn't bend the center cross supports, the bunks are 4 feet off the ground and the bottom of the keel is 18" off the ground as it sits. We need a very high tide to launch and recover.
Over the last 2 years we have done a total refurb on everything in the boat other than the centerboard, so we decided to jack it off the trailer to see how that was doing. I work part time for a guy who sells boat parts, and he showed me how he gets boats off jacks onto his trailers for transfer. It's a lenghty process.
What we did was set two sets of stands under the stern, one about 18 inches off the keel, and the other about a foot off the transom. We re lucky in that there is no cross piece at the stern as to allow the keel to pass. The other two sets were one inside the trailer in front of the keel about a foot, each side, and the other a vertical set OUTSIDE the trailer wheelbase.
That carried a beam made of 2x6s to hold the bow up to allow the trailer to be pulled out from under. The beam itself is made of 6 2x6s , four heavily screwed together in a sandwich, with two others perpendicular to the four. It weighs about 125 pounds, but is very stiff , which is what you need to carry the weight.
Jacking consisted of very slowly raising the four keel stands, then the stern stands , so as to not flex the boat too much. We have had some strange cracks here and there from inadequate jacking before we got her, and I wanted to avoid that problem. The bottom of an Oday is about 3/4" of an inch thick, tapering to about 3/8s at the top of the sheer, but it flexes.
Once we got it high enough, I set up the vertical stands on blocks, set the beam, and started jacking that up, jacking in rotation bow, keel sets, stern, bow, keel sets, stern......This took 7 hours to do.
Once we had the bottom of the keel 40" off the ground we took out the bow interior stands, and pulled the trailer out, carefully avoiding the vertical stands holding the beam . I had taken the bunks off, saving another 8" of jacking. I then blocked the keel, leaving the stern stands up, also resetting the front keel stands ,and it was solid.
So was the centerboard. We pulled out in November, cleaning the hull of the scum the same day. BUT, the CB was jammmed up in the trunk with all kinds of sealife and small mussels-- It was amazing. We had to use a long kitchen knife and spatula to scrape out about 2 gallons of critters to allow the CB to drop....a VERY stinky job....think clams, one month old. We hosed out the remainder, and it all was good.
Setting back down was a reversal of the process, which took about 3 hours.
This is just one method, which worked for us. Joe had some good ideas too, as seen elsewhere. I cannot stress MORE highly that you take your time in doing something like this, make sure everything is chained together, planned carefully, and that you have more enough blocking and stands to do the job. A good sense of humor is vital too- it gets stressfull!
I have an Oday 25 that sits on a bomber homemade trailer - made by a welder. Its one big problem is that because he didn't bend the center cross supports, the bunks are 4 feet off the ground and the bottom of the keel is 18" off the ground as it sits. We need a very high tide to launch and recover.
Over the last 2 years we have done a total refurb on everything in the boat other than the centerboard, so we decided to jack it off the trailer to see how that was doing. I work part time for a guy who sells boat parts, and he showed me how he gets boats off jacks onto his trailers for transfer. It's a lenghty process.
What we did was set two sets of stands under the stern, one about 18 inches off the keel, and the other about a foot off the transom. We re lucky in that there is no cross piece at the stern as to allow the keel to pass. The other two sets were one inside the trailer in front of the keel about a foot, each side, and the other a vertical set OUTSIDE the trailer wheelbase.
That carried a beam made of 2x6s to hold the bow up to allow the trailer to be pulled out from under. The beam itself is made of 6 2x6s , four heavily screwed together in a sandwich, with two others perpendicular to the four. It weighs about 125 pounds, but is very stiff , which is what you need to carry the weight.
Jacking consisted of very slowly raising the four keel stands, then the stern stands , so as to not flex the boat too much. We have had some strange cracks here and there from inadequate jacking before we got her, and I wanted to avoid that problem. The bottom of an Oday is about 3/4" of an inch thick, tapering to about 3/8s at the top of the sheer, but it flexes.
Once we got it high enough, I set up the vertical stands on blocks, set the beam, and started jacking that up, jacking in rotation bow, keel sets, stern, bow, keel sets, stern......This took 7 hours to do.
Once we had the bottom of the keel 40" off the ground we took out the bow interior stands, and pulled the trailer out, carefully avoiding the vertical stands holding the beam . I had taken the bunks off, saving another 8" of jacking. I then blocked the keel, leaving the stern stands up, also resetting the front keel stands ,and it was solid.
So was the centerboard. We pulled out in November, cleaning the hull of the scum the same day. BUT, the CB was jammmed up in the trunk with all kinds of sealife and small mussels-- It was amazing. We had to use a long kitchen knife and spatula to scrape out about 2 gallons of critters to allow the CB to drop....a VERY stinky job....think clams, one month old. We hosed out the remainder, and it all was good.
Setting back down was a reversal of the process, which took about 3 hours.
This is just one method, which worked for us. Joe had some good ideas too, as seen elsewhere. I cannot stress MORE highly that you take your time in doing something like this, make sure everything is chained together, planned carefully, and that you have more enough blocking and stands to do the job. A good sense of humor is vital too- it gets stressfull!
