CBR

Cool! Do you think the neighbourhood zoning commission would approve that? <gg>

I envision eventually building a house with double sided garage doors, roll the boat out into the backyard and davit it into the drink. Storing it outside on a hydro hoist etc in the Florida sun would wreck it in no time I would think. Hence the davit idea. Does not sound practical until you guys invent a counterweighted davit for waterfront homes.

Pantera1

You need a telescoping monrail or rolling gantry crane ..or just do a marine railroad into your garage .. Or just get a boat lift and a canvas ..eureka

mcollinstn

I fixed my bogus calculations.
linked spreadsheet is downloadable to play with.

You'll notice, that the figures in the spreadsheet are MINIMUM figures with no actual "grace period".

And I cannot imagine anybody from the city allowing you to bolt something like this to a limestone plate in a residential area. When it fails, it could affect a whole lot of stuff aside from creaming your boat (adjacent home foundations, underground utilities, etc.). My guess (and I don't know your codes) is that it will have to be stable from a gravity standpoint.

CBR

Downloaded. Thanks Mcollinstn!

Tim G.

Let's just say that I have quite a bit of lift experience....
As far as davits... I've seen way too many failures of the equipment and mounting pads. Davits are fine for 6,000lb, but not for what you're trying to do.
And, you can't grow from a 30 to a 42 without massive reconstruction of the pads...

Don't do it brother...don't do it.
I could type for hours on this, but I hate typing.....

CBR

Thanks for the warning Tim G. Look at my boat, I always like to do things different.
<gg>

I am not about to do anything dumb though.

TopSpin80

here is what I have so far.. I'm off tomorrow and supposed to stay home, so maybe I'll work on it more and do some structural analysis in ANSYS

Ernie

CBR

Topspin80 is about to take out a patent! Looks cool! I am assuming the green simply represents the ground and not a big steel plate. Another key part to see on the drawings would be the underground structure to support it.

TopSpin80

you can drive a 36" piling deep enough to not have to worry about other tiebacks.... just need a soil sample

mcollinstn

Buddy, you paint a pretty picture.

BUT

Surely you understand that the shoreline soil has insignificant outbound support to adequately restrain movement on a loaded piling.

Please don't help this man tear a giant chunk of shoreline out into the waterway. It would ruin his yard...

The "base up" portion of this davit is a non-issue. A handfull of different common crane designs will do the trick. The entire issue exists in the "base down" portion. Show us some magic in that area, then I'll be impressed.