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Old 13-05-2012, 03:03   #1
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Simpson Davits Top Tips

I have Simpson S175 electric davits on my boat, and they have been a bane. After three years of these davits being among the top superstars of the Urgent Repair list, I have finally started to figure out something about their care and feeding, which I would like to share with anyone else who has these davits. The owners’ manual does not have even 10% of the information which one needs to use these davits.


Top tips:


1. Some of you will laugh at me, but I only recently figured out how to adjust the belt tension. It’s not in the manual, incredibly. I didn’t think the belt tension was even adjustable since the belt was buried inside the davit. So I would replace them, they would last a couple of months, then blow out, then I would have to replace them again. In fact, they are easy to adjust, and once properly adjusted, the belts last a lot longer. All you have to do is – with tension off the davit cables -- remove the rear panel, then remove the four slotted screws holding the mechanism inside the davit. Then the mechanism simply slides out the back of the davit where you can get at the adjustment screws.

2. If you rely on the microswitches to stop the motors when the dinghy is fully up, you will be sorry. They don’t work. You will blow belts when the mechanism stalls at the top. Be very, very careful when the dinghy gets to the top. Better yet, bring the dink up the last inch by hand, with a ratchet.

3. The davits come with a cranked 10mm allen headed wrench for emergency hand cranking. This is a pretty poor tool for the job. Much better is a 10mm allen headed attachment for a 3/8” ratchet.

4. If you have to crank them by hand for some reason, it’s better to take the belts off (if you’re cranking by hand because of a blown belt, then this is a moot point, obviously). A huge amount of effort is needed to crank

5. The clutches need adjustment from time to time. They work pretty well when they’re in adjustment. But the clutches themselves are the most incredible Rube Goldberg bit of nonsense engineering I ever saw in my life. The official procedure for adjusting them runs to eight pages! And this procedure has to be repeated over and over again, to get the clutch friction right by trial and error. At the very end of the instructions, there is this note: “YOU COULD TAKE A SHORT CUT AND SIMPLY REMOVE THE END CAP, ROTATE 1 TOOTH CLOCKWISE THEN RE-ASSEMBLE AND TEST. IF THE BRAKE STILL SLIPS REPEAT THE PROCESS.” In fact, that’s all you need to know. There is no advantage whatsoever in the 8-page procedure – it’s still trial and error. Adjusting the clutch tension by just pulling off the cap and rotating it is the right way to do it, and saves a lot of frustration.

6. I have been carrying my Avon 340 dinghy with 25 horsepower outboard in this davits for three years in all kinds of weather, including some big storms with huge waves, with all the weight being carried by the davit lift mechanism. I guess I have to give them credit for being strong enough for this duty. High on my list of things to do is to come up with some way to take the weight off the davit lift mechanism. I tried various ways to tie off the dinghy with lines without any success. Now I’ve just about decided to have some strops made up with Hyfield levers. These would be attached to the lifting eyes in the bottom of the dinghy and to the rings in the davits near where the lifting cables come out. I’ll post about this if I can make it work. I have seen these davits (which are very popular in the UK) with small winches on the sides of them, and with lines taken under the bottom of the dinghies and cranked in with those winches. That looks like a good solution, albeit quite expensive.

7. My davits are rated for 175kg each as a SWL. The actual load of my dinghy is less than half of that (the rib weighs 81kg, the motor 51kg, then say 30kg of console, steering gear, and junk stored on board = 162kg. I would not want to carry any more than that in these davits – the motors are working hard.
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Old 13-05-2012, 03:06   #2
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Re: Simpson Davits Top Tips

Here's the clutch adjustment procedure kindly given to me by the Cooney people:

gearbox_adjust.pdf
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Old 18-09-2012, 08:48   #3
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Re: Simpson Davits Top Tips

Dockhead,

Thank you for taking the time to post this. I have a boat similar in size to yours (Oyster 53) and am looking at Simpson davits as a solution to the headache of launching and recovering the dinghy while at anchor. I actually spoke to Cooney Marine who manufacture Simpson davits by phone this morning (I am based in Seattle) and learned the following.

First, the SWL is for the PAIR of davits, not each one. Therefore, it seems to me given the weight of your dinghy the davits are working at close to maximum capacity. This would explain the frustration you have been having with blown belts, etc. You might want to check that and please correct me if I am wrong here.

Secondly, when I told the salesman at Simpson (Alex) that my dingy with 15hp outboard weighed appx 125 kg, he recommended the Series 8 S300 model which has a SWL of 300 kg. Cost in GBP 5,601.

I am seriously considering installing these but your comments have definitely given me pause for thought.

Cheers.

Dhillen
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Old 06-07-2015, 03:31   #4
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Re: Simpson Davits Top Tips

Quote:
Originally Posted by Dhillen View Post
Dockhead,

Thank you for taking the time to post this. I have a boat similar in size to yours (Oyster 53) and am looking at Simpson davits as a solution to the headache of launching and recovering the dinghy while at anchor. I actually spoke to Cooney Marine who manufacture Simpson davits by phone this morning (I am based in Seattle) and learned the following.

First, the SWL is for the PAIR of davits, not each one. Therefore, it seems to me given the weight of your dinghy the davits are working at close to maximum capacity. This would explain the frustration you have been having with blown belts, etc. You might want to check that and please correct me if I am wrong here.

Secondly, when I told the salesman at Simpson (Alex) that my dingy with 15hp outboard weighed appx 125 kg, he recommended the Series 8 S300 model which has a SWL of 300 kg. Cost in GBP 5,601.

I am seriously considering installing these but your comments have definitely given me pause for thought.

Cheers.

Dhillen
What did you finally do, Dhillen?
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Old 06-07-2015, 03:40   #5
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Re: Simpson Davits Top Tips

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Originally Posted by Dockhead View Post
What did you finally do, Dhillen?
Keep me in the loop, as we have the same pair of squealing davits. They currently work to hoist our 15hp Mercury 2 stroke and hard bottomed Leaky Avon RIB, but they can wake up an entire anchorage with the noisy port side davit winch some mornings. I can't get the clutch mechanism to stop squealing.
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Old 06-07-2015, 04:06   #6
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Re: Simpson Davits Top Tips

I f&&&&&* hate these davits.

One has been out of commission for three years or so -- plastic gear in the motor stripped out when there was a kink in the lifting cable. Ever since I have lifted the light bow of the dinghy with this one using a block and tackle.

I lost the use of the port side one last year the very day I left for my first baltic cruise . The bit which holds the sheave into the lifting mechanism fell out and was dropped in the oggin by a crewman. That's the heavy side with the motor, so I have used various bodges for that since then . Finally this year, I rigged up a nice triple purchase mechanism with low friction eyes which really promised an improvement. Yesterday a friend and I were going to install a rope clutch on the outside of the davit to finish that system, when my friend had the idea to try to repair the normal electric lifting mechanism. We took apart both of them and somehow found enough good parts to assemble one working electric lift mechanism -- hurrah! So now I have one back into commission.

But still, these are absolutely for the birds. I don't know if you've ever taken apart the mechanism, but this is the most cockamamie Rube Goldberg piece of engineering I have ever seen. Vastly expensive to make with all kinds of custom bronze gearwork, but not designed for ****. The one working mechanism I have is not long for this world, because the steel end cap for one of the shafts is wearing through the bronze it bears in


I spent a lot of time on my rope lifting mechanism but I've had a flash of inspiration for a much better, albeit more expensive, but really permanent and elegant replacement for this ridiculous mechanism.

I will simply mount a Lewmar ST30 self-tailing winch on a stainless plate protruding out the back of the davit and made to fit where the existing sled for the mechanism fit. Replace the wire rope sheave with one which will take an 8mm dyneema rope. Run such a rope back through the inside of the davit to the winch, et voila. Mount a cleat on the side of the davit to take the rope tail for safety.

I guess I will carry out this conversion to both davits over the winter time and finally be rid of these problems.

I guess I will spend about $3000, but that is cheap compared to the endless hassle I've had with these. What a joy to have gorgeous Lewmar winches, those totally reliable and almost infinitely long lasting mechanisms, instead of this carp I have now. From an engineering point of view, the Lewmar winches and the Simpson lift mechanism just could not possibly be further apart. Elegance, simplicity, strength, durability versus . . . well, I can't post the bad language which comes to mind. I used to think Lewmar winches were expensive -- until I took one apart and realized what absolutely gorgeous construction and engineering is inside.



As to your squeaking clutches -- you'd better fix that. That must be bronze in bronze grinding, and it won't last long -- it will wear right through. You'd better take it apart and have a look, and lube it up well. If you don't catch it in time, you'll be looking at the same conversion I'm doing.
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