What is going on here? ( Boat Launch )

[MatthewDS]

Browsing a link that Peter R. posted on another thread, I ran across this picture:

http://www.macduffshipdesign.com/ima...1983-large.jpg

Are we looking at a weird accident, or is it standard practice in some areas to run the travellift into the water to launch boats?

This one piqued my interest professionally, as I am a waterfront engineer, and we design a fair number of travelift docks, but I have never seen one driven into the water.

[peter radclyffe]

I have seen it done in france, tho those wooden travelifts did not have engines, they were pulled by a tractor

Strange picture.
Have never seen that either. And it seems there is a lot of water between the Travellift and the dock (left side).

[CatBuilder]

Could be a big mistake. Why?

Take a look at where the engine is on a Travel Lift:




The engine is in the square box labeled, "Marine Travelift 25" in the above picture. The engine could be underwater in the OP's picture. Not great for a diesel.

However, I have seen other Travelifts (not the name brand) that have them mounted a little higher, on that beam that is only partially submerged. (see the Acme brand travelift below):





I'm assuming in the OP's case, the engine is on the horizontal beam that is still out of the water, not seen behind the boat being launched. Still, that has to severely shorten the life of the Travelift. Bad practice for sure.

[Richard Woods]

As I recall the travel lift in Queen Anne Battery marina, Plymouth UK, runs in the water daily

Richard Woods of Woods Designs

www.sailingcatamarans.com

[MatthewDS]

@Richard Woods,

Interesting, I visited the Queen Anne Battery marina website, and sure enough, there was a picture of a travelift operating in the water:

http://www.mdlmarinas.co.uk/mdl-quee...e.asp?ID=52246

Does anybody have any idea why you might want to do this? It seems to me that any cost savings that you see by not building a launching dock would be offset by the need to replace the travelift more often.

[peter radclyffe]

the driver is an offroader

[peter radclyffe]

lets guess, launching dock 1 million, travelift 1/4 million, sure a dock is better & safer

[TeddyDiver]

I don't see any problem with this with bronze bearings or fresh water.. but never seen before.

[cthippo]

Look at where the engine box on the Queen Anne lift is as well. The feasibility of this would appear to vary with model.

[Richard Woods]

QAB was originally a float/seaplane base (yes we had them in the UK as well) so it had two big slipways already and nowhere to put a travelhoist dock (remember tides in Plymouth are about 6m 20ft)

Richard Woods of Woods Designs

www.sailingcatamarans.com

[Fanie]

This one seemd to be pushed in with a vehicle.

[Easy Rider]

Maybe the engine is on the other side (high) and there was a problem w the structure that usually supports the travel lift like a boat ran into it and it was'nt safe so they had a ramp or sloping surface and used it. May have something to do w the odd boat in the slings. Perhaps it was sinking and the travel lift dock was being used so it was a save the boat act???? Guesses!

[SamSam]

A travel lift that can submerge can be used at almost any ramp, anywhere. It would seem to be a lot more versatile.

[Commuter Boats]

Look at the mounting for the winches as they're also a little unusual. My guess is that that's the normal operating procedure for that lift. A Marina with a wide ramp could accommodate more than one width of travel lift which might provide some economy.