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Old 08-01-2016, 09:07 AM   #1
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Davit installation

I came across a great deal on a 1000 lb davit crane and need some advice with the installation. I'll be putting the 130 lb unit on the upper deck of a 36' Krogen Manatee and have two concerns...

1) Should I install it at an aft corner so as to distribute the weight across the rear when stowed rather than a side mount where it may cause a list?
2) I'll need a pipe/pole to mount it on, this will be anchored to the lower aft deck and penetrate the upper deck to suspend the crane at or just below rail height. My question is, do I need some type of metal pole or would several PVC pipes embedded in each other be strong enough?

The heaviest thing I'll be lifting is a 10' rib with a 9.9 hp motor.
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Old 08-01-2016, 09:29 AM   #2
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The davit installation will end up heavier than 130lbs by the time you support it and reinforce the boat structure. Even so, you could readily compensate for the trim by storing stuff differently in the boat.

Poke around the 'net. Lots of choices to be seen for where you put the davit's support post. Just aft of the salon's aft corner, for example. It would be less intrusive there as well as profit from the presumably-well-supported decks there.

Do you really want to use up Flybridge square footage with a dink and its cradle? Where would you put your beach umbrella and potted palms?

PVC pipe is quite useful stuff but is neither very strong nor stiff for its weight. It also creeps under load over time. Sleeving pipe within pipe does not gain you much in bending or buckling loads since the 'extreme fiber', the outside portion of the structural shape does most of the work.

Your mention of a pipe or pole to mount it on suggests that the p. or p. is a stub onto which the davit sockets. If so, the p. or p. will be quite heavily loaded in bending where it passes through the upper deck. A stainless steel or aluminum tube would have to be evaluated, engineered so as to make it as thin, light, and thus cheap as possible as well as strong enough.
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Old 08-01-2016, 02:18 PM   #3
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Our support pole is just aft of the step on the port side. You can see it in this picture. We didn't design the install. We've only had the boat 3 weeks or so. I'd talk to Larry (healhustler) or ask on Krogen Cruisers. Good Luck!

Well, posting the image didn't work. Here's a link to the image in my album here on TF.

http://www.trawlerforum.com/forums/m...icture3137.jpg
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Old 08-01-2016, 02:48 PM   #4
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perhaps someone at kk could help you,as their support for kk owners is legendary
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Old 08-01-2016, 03:13 PM   #5
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Thank you gentlemen, good info. I'm also trying to determine if I actually need a dinghy or not. We are starting the Loop in a couple of months, we'll be taking along two kayaks, we have no animals to transport, we'll be anchoring out sometimes, staying on a ball sometimes and staying at a dock sometimes. If we want to explore a river, creek or swamp we can use the kayaks.
Plus DHeckrotte asks a good question, where will I put my beach umbrella and potted palms?
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Old 08-01-2016, 03:24 PM   #6
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Here's a link to a dinghy crane installation posting oon TF a few years ago. Scroll down after selecting link.

Bring the Dink aboard.
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Old 08-01-2016, 03:56 PM   #7
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Manatee, I've just purchased a couple of rod holders to install on railing stanchions for mounting our beach umbrella. It's a handy, quick way to shade a seating area if the boat's orientation and the sun are not cooperating. We've used this umbrella for many years mounting on the binnacle of the sailboat even when sailing (downwind in the Chesapeake, with the boom prevented from gybing).

I am, by the way, making a light davit for my ease or my wife's capacity in launching and retrieving her kayak from its storage place on the flybridge 'wings'.
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Old 08-01-2016, 04:04 PM   #8
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River Rat, Congratulations on the purchase of a fine boat!
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Old 08-01-2016, 04:46 PM   #9
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Thanks! I followed your blog for a bit when I was doing my Manatee research. Or manatee stalking, as it's been called! 😄 if it was about a Manatee and on the Internet, I probably found it.

So many Manatee owners were very helpful. My husband and I are looking forward to being in the KK family! Let us know when you're on the Annapolis portion of the Loop. We'd love to introduce Overtime to Sabrina.

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Old 08-01-2016, 06:08 PM   #10
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I can't imagine doing that cruise without a dinghy. Kayaks are going to get pretty old pretty quick for shuttling supplies and people back and forth to the anchorage or mooring field. Or are you actually just planning on docking everywhere?

What make of davit is it? The manufacturer will have the specs for what type of pole it needs.
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Old 08-01-2016, 06:11 PM   #11
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Quote:
Originally Posted by Manatee View Post
Thank you gentlemen, good info. I'm also trying to determine if I actually need a dinghy or not. We are starting the Loop in a couple of months, we'll be taking along two kayaks, we have no animals to transport, we'll be anchoring out sometimes, staying on a ball sometimes and staying at a dock sometimes. If we want to explore a river, creek or swamp we can use the kayaks. :
Hello Manatee, FWIW this is my dinghy discovery.

When I bought my current boat four years ago, I thought that the dinghy (pinnace really) arrangement was overkill and I would soon be replacing it with something "sensible".

I had always used a dinghy that was sized according to stowability - either on the foredeck or deflated in a locker. Manhandling on and off and inflating/deflating was a chore.

Well, the previous owner knew something (and had the funds) that I didn't.

My 12ft, 30hp RIB on hydraulic stern davits has added new dimensions to my cruising. Transporting supplies, exploring distant creeks, fishing, picking up guests in congested areas - all easy and fun.

I'm not a Kayaker, but I reckon your proposed davit installation for a reasonably sized, easily deployed dinghy is a good idea.
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Old 08-01-2016, 06:42 PM   #12
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Thanks Larry, the davit you built is what I'm looking for. I came across a great deal for a UMT Econo 1000 lb crane but feel it's overkill for my boat/dinghy arrangement. I may go ahead and install it but if I can come up with something like you have I'd go with it instead.
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Old 08-01-2016, 09:13 PM   #13
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Manatee, a good source for having someone make the davit is a motorcycle shop that builds custom frames. They can size the pipe, bend and weld it to your plans, they also could make a compression post.
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Old 08-01-2016, 09:44 PM   #14
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Originally Posted by HiDHo View Post
Manatee, a good source for having someone make the davit is a motorcycle shop that builds custom frames. They can size the pipe, bend and weld it to your plans, they also could make a compression post.
Another source for fabrication help would be a shop that makes SS boat railing.
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Old 08-01-2016, 11:22 PM   #15
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Quote:
Originally Posted by Manatee View Post
Thanks Larry, the davit you built is what I'm looking for. I came across a great deal for a UMT Econo 1000 lb crane but feel it's overkill for my boat/dinghy arrangement. I may go ahead and install it but if I can come up with something like you have I'd go with it instead.
I think that crane would work just fine, but you'll be in need of some heavy duty hardware to mount it, including through bolted spreader plate on the boat deck where the stand pipe goes through and an equally beefy base plate on the veranda deck. Make sure you center the hole in the veranda ceiling between cross beams,....that way you can use flat plate the full width of the area between the beams. Make sure the stand pipe sits on TOP of the base plate, otherwise using the crane at full capacity will end in a hurry. Use Mfgrs. specs for standpipe size.
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Old 08-02-2016, 06:11 PM   #16
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Thanks everyone for your input, I've got some thinking to do... and that always hurts.
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Old 08-05-2016, 02:28 PM   #17
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which is supporting which

Quote:
Originally Posted by eagle419 View Post
Hello Manatee, FWIW this is my dinghy discovery.

When I bought my current boat four years ago, I thought that the dinghy (pinnace really) arrangement was overkill and I would soon be replacing it with something "sensible".

I had always used a dinghy that was sized according to stowability - either on the foredeck or deflated in a locker. Manhandling on and off and inflating/deflating was a chore.

Well, the previous owner knew something (and had the funds) that I didn't.

My 12ft, 30hp RIB on hydraulic stern davits has added new dimensions to my cruising. Transporting supplies, exploring distant creeks, fishing, picking up guests in congested areas - all easy and fun.



I'm not a Kayaker, but I reckon your proposed davit installation for a reasonably sized, easily deployed dinghy is a good idea.

John,

Interesting install and I like the look. How much weight is being supported by your mast or are the cables from the davit to the mast, stabilizing the mast?

Thanks
Gordon
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Old 08-05-2016, 05:04 PM   #18
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Hello Gordon,

I don't know the weight the dinghy and motor, but the davits are self supporting.

The mizzen backstays and the aft deck awning supports terminate on the davits for convenience.

cheers, John
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Old 09-02-2016, 07:50 PM   #19
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Here's the rest of the story...
The davit-crane I bought from a guy at my marina was from UMT Marine, I gave them a call and wound up ordering a standpipe. It arrived about a week later, was 10 ft long aluminum with 3/4" walls and had a circular plate welded about 18" from one end. There were three other pieces with the order, an aluminum plate for the under-deck, a base "cup" for the lower deck and a plastic cover for the welded above-deck plate. I've attached an installation diagram and pictures; the installation diagram is for a hydraulic unit which mine is not.
After getting up the nerve to drill a 4 1/8 inch hole in my upper deck in a location I pondered about for several weeks I was off and running. Turns out there's a 5/16 inch gap between the aft deck plastic ceiling and the wood fiber + fiberglass upper deck; this was a problem because it would leave too much play between the plates once installed. I was lucky enough to find some 5/16 inch square dowels which I cut into 3 inch lengths to stuff into the gap. A friend also suggested I use "Six 10" epoxy to seal the gap so no moisture could get in and for additional strength.
With the hole cut I was able to install the standpipe to determine how much needed to be cut off, UMT recommends measuring at the boat rather than having them do a custom fit. I measured 21 inches to be removed from the bottom and found a good machine shop to do the work. The under-deck plate was too big to fit between the ceiling ridges so I had them trim those as well. I sprayed a zinc coating on the cut surfaces to prevent corrosion.
I reinstalled the standpipe to determine where to screw down the base cup then after securing the cup I drilled a hole in the center for the electrical wiring used in operation of the motor. After running the wire from below the bottom aft deck through the cup, up the center of the standpipe and over to the crane all I needed was some help to put it in place.
This took several days and was more difficult than I've made it sound here due to trial and error and multiple trips to the hardware store. I'm discovering through all the work I've done on this boat, that if I stop doing things simply because I don't know what I'm doing, I never will get anything done!

I hope this helps anyone else considering a similar task.

https://drive.google.com/folderview?...U0&usp=sharing
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Old 09-03-2016, 10:02 AM   #20
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"I'm discovering through all the work I've done on this boat, that if I stop doing things simply because I don't know what I'm doing, I never will get anything done!"

True! We haven't attempted anything as large as you have, but we feel the same. Each new task is a learning experience. You only have to learn how to do something the first time. Then you know it. :-) hopefully.
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