Lift winch help

I need a little help from the engineering folks out there. Actually, I just need you to tell me if I am right or wrong with my thinking.

I need to buy a new electric winch for the lift. The specs on my current winch say it is rated at 3000 lb dead weight vertical lift. My boat is about 3500ish lbs loaded. I have a cantilever style lift that routes the line down from the winch, to a pulley on the front corner of the cradle to a pulley on the other side, and then back up to the other front leg of the lift. By my calculation, that means there is a mechanical advantage of 2. The two moveable pulleys, because they are traveling in the same direction, function as if they were one pulley. So with this set up, my winch rated at 3000 lbs dead lift, would be theoretically capable of 6000 lbs. Does that all sound right?

The reason I ask is because the current old winch struggles to raise the boat. I want to make sure if I replace with the same unit, new, it should preform better. Also, I have the opportunity to switch to a 110v AC unit rated at 2700 lbs. It is GFI protected, and I could eliminate the battery, solar panel charger (do not have one yet), etc and I could add canopy lights, etc, but with the lighter rating, wanted to make sure it would be able to lift the load.

Let me know if I am way off or missing something.

Thanks guys.
Adam

Adam,
Your thinking is correct. A cable down and then back up cuts the load on the winch in half. Same principle as a block and tackle.

Can anyone point out any disadvantages of going to the AC unit, besides the obvious electricity and water deal? GFI should protect us there (it is working, I tested it when we moved in). I am thinking it would be really nice to eliminate that battery...one less thing to think about maintaining. I already have power down by the dock, and it is only 60 ft out to the lift. I can just zip tie the cord to the underside of the dock.

Adam,
I forgot, you'll also need to know the wire size in the run from the panel to the winch too.

The only other thing I can think of that's bad with an AC system is if you by chance get caught out on the lake during a power outage. When I electrified my winch, I maintained the hand wheel just in case!

voltage drop calculator

FWIW- I have a 24volt winch which requires two batteries. I have a solar panel to charge them. I use the boat at least one or two times per day (unless raining) and go full up on each session. The batteries last the season without having to charge them. Other that lifting them up and down twice a season to install and remove before storage they are always at the ready. Boat goes up to full lift height in less than one minute.

My lhe lift has a big screw jack that does the lifting. Quick, quiet, but the motor mounts differently than a conventional model and may not fit. The lift is made by Floe.

Floe

harddock wrote: FWIW- I have a 24volt winch which requires two batteries. I have a solar panel to charge them. I use the boat at least one or two times per day (unless raining) and go full up on each session. The batteries last the season without having to charge them. Other that lifting them up and down twice a season to install and remove before storage they are always at the ready. Boat goes up to full lift height in less than one minute.

Floe is a nice lift. A little pricey for me though. My decision to switch to AC was because of a couple reasons.
1. My current battery is shot for the lift - $100
2. I do not have a solar panel to keep it charged - $150ish with stand, etc
3. I can add canopy lights
4. I have power near the dock already

All that added up and the manufacturers 2 year satisfaction guarantee and performance claim (same for his DC unit) pointed me to his AC unit.

azeus17 wrote: The claim is the same for AC or DC drive...4000 lbs 4 ft in 1 minute. I can get back to you on that sometime next week after I install mine.

Then it should take abour 2 minutes to raise the boat/lift.

Look at the site posted above...they produce a winch that can replace your manual winch for just about any lift. Give them a call. Mike was great to work with.

Mine arrived Monday, btw, and I hope to install tonight. I will post my results.

kenowja wrote: what could you do if you want to upgrade a lift without a Electric winch, you know, the hand crank style... its getting annoying having to crank up the boat every time i take it out. can i get a winch that would just bolt on or what?

Jake,
I'm confused here with your question. Without going electric, it will still require the manual effort to crank it up. About the only thing you can do to reduce the effort is to double the winch ratio but that will also double the time it takes to raise the boat. I'd say you would still be burning up roughly the same amount of calories!

i have a shore station, dont know what model, but it has the wheel

ok thanks, well i hope to get something pretty soon

quinner wrote: Adam, really curious to see how this one works out, do you need to remove the wheel to install it?

No wheel on mine. I have a DC winch on there now that is burned out. Was going to install yesterday, but got held up at the tire shop. Tonight is not looking good either as the wife signed us up for dinner at the neighbors. Tomorrow is my first "flex friday" of the season, so I should get to it then.