Davit failures

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LookingGlass
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Davit failures

Postby LookingGlass » Wed Jun 08, 2016 6:49 am

I've read here of several early model davits that have failed. Since we're getting ready to upgrade our dinghy and motor (heavier), I wonder about strengthening my davits. Can anyone tell me where the early davits have failed? They look pretty strong to my eye. Is it the stainless that fails, or the fiberglass ledge on which the davits sit? Thanks for the help.
Mark Richter, Ortona, FL
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duetto
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Re: Davit failures

Postby duetto » Wed Jun 08, 2016 2:09 pm

hi mark,

we had a davit failure about 7 years ago. the davit failed by collapsing (albeit not completely). i believe that on the early boats (we're #23) the davits had thin wall ss with not a lot of reinforcing at the bends. we were carrying a 9'6" ab with a 15 hp 2 stroke. being honest we didn't have it strapped down super tight and the waves were steep and close. so i guess it depends on what you plan to carry.

we replaced them with st croix davits rated at 450 lbs.
john & diane cummings
duetto mv34 #23

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Re: Davit failures

Postby deising » Wed Jun 08, 2016 3:06 pm

I can't comment on the early PDQ davit weaknesses, but I know that making sure the load (the dinghy) is securely strapped and cross-tied to minimize any dynamic loading is critical. Dynamic loads can be over twice the static load.
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Re: Davit failures

Postby Tanah-Keeta » Wed Jun 08, 2016 4:34 pm

I used to own hull # 108 and the davits were strong. I left the drain plug in my dingy once and it completely filled with water with no issues except my embarassment.
Ron McDaniel
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Re: Davit failures

Postby Cat Daddy » Wed Jun 08, 2016 7:50 pm

I had a davit failure in April. On the Neuse River in a fairly rough chop. The dink had lost some air over a few days and was not secured as well as normal. The swinging motion certainly makes the problem worse. The engine side collapsed in the main tube at the lower bend. It was repaired at Atlantic Yacht Basin by their SS welding contractor. He did a great job by replacing the tube with another that is twice as thick, reusing the original bracing and mounts.

If I were planning to solve this problem before it happens, I would consider St. Croix davits. I saw a set that are installed on PDQ hull #34, "Beach Magic", and they look like a massive improvement in strength & usability.


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Re: Davit failures

Postby Katlin » Fri Jun 10, 2016 1:03 pm

Mark. I had a failed davit experience with the 'older' style davit (I have hull number 76). Do a forum search for my May 19, 2012 posting on failure with pictures and Sept 01, 2012 resolution. I currently carry a 9'3" RIB with 70 lb motor without any issues.

John Sawyer
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Re: Davit failures

Postby thinwater » Sat Jun 11, 2016 3:30 pm

I wonder if dinghies have gotten heavier; RIBs were rare back when, and a 9.9 was a big engine. Did they come with specs?

Fortunately the PDQ 32 davits are ridiculously strong. I carry a dinghy, 2 kayaks, and sometimes walk on them too.
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Re: Davit failures

Postby Katlin » Thu Jul 07, 2016 1:09 pm

Our failure was at the elbow (old style davits) which we subsequently had reinforced (by original davit manufacturer in Canada) with a box style brace welded to reinforce the elbow. Never any issues with fiberglass mounting platform.

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Re: Davit failures

Postby DickTuschick » Fri Oct 14, 2016 3:43 pm

The davits that were supplied by the factory were rated at about 150 lbs and they recommended that a dinghy and motor of less than 100lbs be used. We tested these davits by hanging 150 lbs on each one (with a little springing on them and had no failures) However....as noted in another posting that is static load. The real problem comes in when the dinghy is not secured properly and a lateral "shock" load can occur equal to MANY hundreds of pounds from an angle which the davits were not designed to handle. So....the dinghy MUST be secured properly or failure is highly probable. A dinghy that is secured properly should not have more than one inch of lateral movement. This can easily be achieved by using ratchet straps in an X configuration and then "socking in" the bow and stern.
In the case of the PDQ 41, different davits were supplied with the boat but the problem was identical. Failures occurred...always due to the dinghy not being secured properly.

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Re: Davit failures

Postby AMCarter3 » Fri Oct 14, 2016 4:07 pm

I have a 2006 PDQ Cat. I believe this is about the year PDQ upgraded the davit structure. Ours seems very strong. However, I totally agree with Dick -- "the dinghy MUST be secured properly or failure is highly probable. A dinghy that is secured properly should not have more than one inch of lateral movement. This can easily be achieved by using ratchet straps in an X configuration and then "socking in" the bow and stern."

After hearing and seeing pictures of this "X configuration" method for securing the dinghy from some other PDQ owners, I started doing it immediately. I used dock lines instead of ratchet straps due to the absence of a tie-down ring inside the bow of our dinghy. The rope method is almost as good as what I imagine can be done with ratchet straps. It virtually eliminates lateral movement. I use a 3rd line that pulls and snugs the dinghy to the vertical upright poles in the davit structure to reduce fore/aft movement. This combination was well tested in some 5-6 upwind runs in open water in 4-5' very choppy seas recently. The dinghy was steady and moved with the boat's movement -- which is exactly what you want.
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Re: Davit failures

Postby thinwater » Sat Oct 15, 2016 3:16 pm

Tricing lines are even better. I have had tackle failures that dropped the dinghy in the water underway. Not fun.

Now I can actually release the lifting tackle and the dinghy stays. No motion either.

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Re: Davit failures

Postby Katlin » Tue Oct 18, 2016 4:17 pm

Hi Mark

Do a search of this powercat forum for my postings of May 12 and Sept 1, both in 2012. Be pleased to answer any Qs they don't answer.

John Sawyer
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