Davit system for heavy loads

[infy]

I'm in the market for a new davit system and someone selling a used Nick Jackson transom davit suggested this is the community to talk to.

I'm looking for the capability to lift at least 1000lbs. There are a couple of reasons for that. Primarily, my tender is a 12' Rigid Boat which I really like. It's roughly 500 lbs with the engine, cooler, and other supplies on board. I'd prefer to have a davit which is rated for far more than 500lbs to have a healthy margin. Also, there are other things I would like to have on the davit which approach 1000lbs.

There are two ways I have in my mind for mounting the davit.

1. With the legs directly on the transom and a large backing plate to distribute the load. This one is tricky because my transom is angled at 15* or so down the middle. Kind of like this carrot < viewed from above.

2. The legs on the swim step. But my swim step will certainly require reinforcement from below. This is the direction I'm leaning to.

I don't have the space or layout for a crane. This isn't a trawler. It's a Bayliner 4285 with a 46' LOA. I don't have a drone shot of my vessel, but I attached a photo of another to give an idea of the layout.

My main question here.. How to best go about doing a safe installation for the 1000lb load?

 

[Simi 60]

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My main question here.. How to best go about doing a safe installation for the 1000lb load?

Speak to a business who makes them preferably one who knows your boat

I don't have the space or layout for a crane. This isn't a trawler. It's a Bayliner 4285 with a 46' LOA. I don't have a drone shot of my vessel, but I attached a photo of another to give an idea of the layout.

First thing I noticed is that it has what looks to be a crane

 

[Larry M]

I’d call Nick Jackson. We had their 800lb low profile unit and loved it. We were told we could upgrade it to 1200lbs by sleaving the vertical support which we never did. With Nick Jackson based in the the PNW and some Bayliners manufacturer there I’d think they’ve installed one or two a sister ship.

 

[Portage_Bay]

In a properly engineered, built and installed system there shouldn't be any need for a 100% over capacity davit. Adequate safety margins should be in the system. A conversation with the davit builder would be in order.

A consideration often overlooked in DIY installation is the base and support. The high capacity davit is no good if what it's mounted to fails.

Sent from my SM-A125U using Trawler Forum mobile app

 

[garbler]

Davits or lifting booms are engineered and rated at testing facilities under static loads with very specific provisos that the product is properly installed. Almost every davit failure I’ve inspected occurred from abrupt dynamic loads such wakes, waves or other similar conditions. Large doubler or backing plates can spread the load but can also create serious stress risers putting the hull skin laminate into a shear load along the perimeter if the skin is of marginal thickness and strength. Do plenty of homework

Rick

 

[infy]

First thing I noticed is that it has what looks to be a crane

That's a passerelle. In Europe, particularly in the Med, you're often required to dock stern to. Practically every boat out there has a passerelle / gangway.

 

[infy]

I’d call Nick Jackson. We had their 800lb low profile unit and loved it. We were told we could upgrade it to 1200lbs by sleaving the vertical support which we never did. With Nick Jackson based in the the PNW and some Bayliners manufacturer there I’d think they’ve installed one or two a sister ship.

I like the idea of calling Nick Jackson. I'll do that Monday. I'm not very hopeful that they have any experience with this boat though. There were less than 10 built. Two years of design from a clean sheet.

Here is where it helps to have a mass-produced product. Lots of accessories, expertise, and existing solutions.