Dingy crane weight limit?

[tobyyost]

I have a crane for the dingy on my 1980 gulf star 44. Anyone know how to tell what the weight limit for it would be? I can't find anything on it that would tell me. Any thoughts are appreciated.

 

[Giggitoni]

Do you have the manufacturer's name and model number? I have a Roskelley/Olsson RBH-3 with a rating of 1,000 pounds.

 

[Deano]

I also have a 44 and the crane has no markings also. It does have an old Rule winch which is rated for 500#. It was my guess that would be the rating for the boom as well.

 

[healhustler]

SS, alum, pipe style, gotta back bone on it, what size cable?? Photo might help too.

 

[txman65]

I have 1985 Mark II MY, with a 5 inch diameter Davit/ hoist that has no problem with my 10 ft Boston Whaler and 35 hp 2 stroke Evenrude.

Did upgrade the winch to 1000# capacity couple of years ago.

 

[Larry M]

I know the term "winch" is used pretty regularly when we're talking about our dinghy cranes. When I was looking for a spare I was reminded that there is a difference between a hoist and a winch and I should buy accordingly.

"A hoist is for lifting and a winch is for pulling. A Winch is geared for pulling a load on a relatively level surface. A winch uses a dynamic brake that must slide. A Hoist is geared to lift (dead weight) and has a locking brake that can support a "hanging" load."

 

[tobyyost]

pictures of labels

So I was up on the boat this weekend and got some pictures, I tried to attach them, so not sure if you will see them or not. There were more tags than I had originally seen. So based on this it looks like it is a marquipt lift. on the winch, which is a GOLO made by CORDEM it says maximum lift first layer 1200, full drum 700. So based on this am I correct to assume that if I only have one layer of cable, which is all I have, that the capacity of the entire unit is 1200 LBS? Let me know your thoughts. Thanks.

 

[dhays]

So you are saying that your cable lays along the surface of the drum and never lays on itself? If that is the case, then 1200lbs. Keep in mind that would be when it was in its as-new condition.

 

[Larry M]

So you are saying that your cable lays along the surface of the drum and never lays on itself? If that is the case, then 1200lbs. Keep in mind that would be when it was in its as-new condition.

What he said but that's for the hoist only not the system. We have a Nick Jackson davit system with a Warn hoist. The system is rated for 800 lbs. The Warn hoist is rated for 1200 lbs with one wrap on the drum of 13'. Two wraps is rated for 1090 lbs with 27' on the drum. With the hoist fully retracted, with extra line, we have 3 wraps on the drum or about 1000 lbs rated.

 

[dhays]

Good point Larry. I'm not familiar with his system at all.

 

[BandB]

You need to contact Marquipt and get the rating for your crane. You need that, not the capacity of the wench. I'm assuming you don't have a Marquipt model number?

 

[Marlinmike]

A lot will depend on how well it was installed. Had a real nice block and tackle on my sport fisherman, nice large welded rings, first time I used it found out the owner/installer used lag bolts, needless to say, what looked like something for a large shark or tuna really could only handle a flounder, that is until I changed the mounting methods.

 

[tobyyost]

Thanks for all your comments. I was wondering if this thing could handle a smaller two seater jet ski, like maybe one of those sparks, which I think run around the 700 something mark. I am very concerned to try it though. I see that marquipt is still in business so I will contact them to see if they have any details. There are a lot of variables here and I would hate to tear something up. As far as mounting, it is mounted on top of sort of a well casing that seems to go down through to the hull of the boat, so it goes through the roof, then through the decking, and then ends up in the bilge area somewhere, but I have not tracked that down yet. The unit sits on top of this casing, and then appears to be lagged to the roof, as I see no plates or anything on the bottom side of the roof. Well I guess I will go to marquipt first and then decide if I even want to attempt it from there. Thanks for all your thoughts.

 

[koliver]

You need to contact Marquipt and get the rating for your crane. You need that, not the capacity of the wench. I'm assuming you don't have a Marquipt model number?

IF you ask her, she should tell you the capacity, though that may vary depending on how she is asked.

 

[BandB]

IF you ask her, she should tell you the capacity, though that may vary depending on how she is asked.

Wifey B: Can't believe he didn't catch that. He knows this wench's capacity though.

 

[GMB]

Similar line of discussion, different aspect. What is the safe working load for the aft hardtop in say 4-6 ft seas?

 

[caltexflanc]

Similar line of discussion, different aspect. What is the safe working load for the aft hardtop in say 4-6 ft seas?

What boat? What exactly do you mean by working load?

 

[GMB]

What boat? What exactly do you mean by working load?

Please consider the context of my reply. OP has a " 1980 gulf star 44" let's assume it is a MC model but the MY model may have the same aft deck hard top.

To learn about SWL you could _start_ here
https://en.wikipedia.org/wiki/Working_load_limit

Considered loads should include dead load (weight) and live loads (wind, accelerations due to sea state dynamics). In selecting a factor of safety, I would think frequency response of the load path and failure mode of the structure should be considered. Remember FRP goes from linear response to fracture in short order.

But really I'm looking for anectdotal accounts of dingy size and sea conditions tolerated.