Another boat lift question

Check Overtons. Their Doozie lifts kind of have a diagram that may give you some ideas

Thanks harddock ~ my friend at the lake has the Doozie or a very similar model lift in his double boat house.   

His neighbor next door has the vacant boat house.

TXFoilhead ~ The low water senario does make a bow stern eye lift sound best.

I have had two Ace boat hoists. One cradle and one 2 point lift. The two point lift is basically a motor attached to a pipe with two cables. Pretty simple, but, as Pete said, you need to make sure the rafters will hold it.

For the rafters to hold it, all you need is to double up two 2x6's for a span of 10' or less. That should cover your typical boat slip. The 2x6's should rest directly over the pilings. We've been building boat houses for 40 years. That's how most of them are done.

A little trick: When you make the holes in the pipe for the cable attachment, drill at an angle so they are offset. This will make the cable wrap down the pipe and not wad up.

Also, you can use two conveyer belts as opposed to a cradle with pulleys set to the outside of the rafters. The belts just cradle around the boat, any boat, no customization necessary and they need practically zero water depth so you don't lose any headroom in your boat draft. It's much easier on the boat quite honestly than constantly using the lifting eyes.

You make some good points about the hazards with an inboard boat but it is definitely overcomable. Since he is building the lift, he can set the straps where that shouldn't happen with the shaft. As for the tracking fins you just have to lower the belts more. The back belt is sometimes slightly lower than the front but it depends on where your drain plugs are located. The bilge needs to be drainable.

As for your friend's Glastron. We've been hanging boats with slings for years and never had that problem. The cables should be out wider than the gunnels. We usually set ours all the way to the edges of the slip. This keeps the boat from pinching in the sling. Check the position of his pulleys. If the boat is squeezed and the pulleys are well past the gunnels of the boat, then I would suggest he has other structural problems.

However, if you can get a cradle, that's definitely the best idea just not always the cheapest or most practical. 3ft of water isn't much.

I've been slinging mine for years and I use a garage door opener to lift it I'll get pictures in the morning

Gary S wrote: I've been slinging mine for years and I use a garage door opener to lift it I'll get pictures in the morning

A garage door opener?? !!! I motorized my lift with a DC gearmotor. I picked it due to worries about the voltage drop all the way from the house to the lake. With the DC, if it sees less voltage, the only thing that happens is it runs slightly slower!

I want to see your set up so don't forget the pictures! BTW, Mine is set up so it's able to be disconnected from the drive with a couple of "T" handle pins. Just in case of a power outage, I still want to be able to go boating!!   

This method of slinging the boat also checks your stringers,when it folds in the middle,they need to be replaced.

Gary,
Cool!! Great back yard engineering and it fit's right in with the other lifts on the river!! Why did he choose the slings? No lifting rings on the Shamrock or not enough support across the top?

Thanks guys-great tech advice.   I appreciate the discussion.   My friend and his neighbor are both builders.   The neighbor with the boat house is 20+yrs past retirement.   The boat house is not strong enough for a lift, but I might could make necessary improvements.     I'm out of town right now - pics the following weekend.   I'm more comfortable working with steel / but they both have poles timbers and heavy equipment available.   I like the worm gear drive on the doozie style lift.

Also Pete, the roof structure itself is tied to these cross members so the load transfers better across the span than just the two 2x6's. In 40 years, we haven't lost one yet. The liability insurance is doing fine LOL.

Why don't you come on down and have a beer with us? You'd be amazed at what we can do with duct tape.

Pete's got me thinking a little. I'm actually more concerned with what kind of uprights it's sitting on and their condition. Send some pics.

Just so you guys are comfortable, my dad is one of only 5 deep piling contractors in North Texas. We built a platform to support a triple deck gas well drill that weighed a million pounds with a million pounds of pull back. Oil and gas companies are in a hurry so we built it on the fly from the seat of the machinery we used to do it. We developed soil cohesion data from the drive characteristics on site. They didn't want to wait for us to put the cross members in and we predicted a 1 to 2" sink in one corner depending on their pull back. They got 1 as predicted and we didn't even break out our slide rule. We mobilized, designed, and built a $600,000 support platform in less than 10 days 7 feet from a live gas well with sparks flying everywhere. If you're not familiar with gas wells and steel driving, they don't mix. Ya gotta know your doodoo man.

Send me pics. If the old man says 2x6's will hold, they will hold. And I checked with him. He says if you lift from the eyes it will take more support.