aVON HEAVY ON DAVITS??

[stefan]

just replaced my old Avon Seasport 345 + Merc 25 with an Avon Jetrib 320, that I expected to weigh about the same with better weight distribution. As it turned out the new tender is heavier (250 kg) with more weight on the stern. It feels tough on the winch handle! Does anybody have experience as to the performance of the davits on old Princesses (P55 -89)??
The winch wire is 4 mm. I am also conserned about the laminate where the davits are connected to the hull. I remember seing some boats with crackles in this area in the past.


<hr width=100% size=1>

 

[markc]

Hi - what davits do you have? I doubt that they will be strong enough for the Jet Rib - I have a 345 seasport with a 30 Mariner on some large Whittal davits, but I certainly wouldn't try to carry a Jet rib!!

M

<hr width=100% size=1>http://www.geocities.com/jinto100/Jintopics.html

 

[PhilF]

ah, but he is an enteprenneur!!

<hr width=100% size=1>

 

[Deleted User YDKXO]

Agree with mark. For a 250kg total load, you need davits with a lifting capacity of 250kg EACH which I very much doubt you have. Most davits fitted to older boats will have a capacity of 100-150kg but it should be easy to check as the davits normally have a serial plate fitted to them. If not, take some measurements and consult the manufacturer (likely to be Whittall or Simpson (now Cooney). Possibly Princess themselves may have a record of what davits were fitted originally
Definitely worth keeping an eye on the grp mountings and fixing bolts as well

<hr width=100% size=1>

 

[robind]

Hi Stephan
I agree with the previous posts here, they may be a bit light, however check with the manufacturers as to what their safety factors are? and should the mountings appear to be stressed you can always reinforce these underneath with GRP or Polished Stainless plate, incooperating further support brackets on the top of the gunnel or down to the deck.
Hope this helps

Regards

Rob. P.O.G.

<hr width=100% size=1>

 

[Talbot]

I would be very concerned about using a 250 kg rated davit for a boat weighing 250 kg. The snatch load when initially taking up the weight will be considerably more than that, especially if the dinghy is on a down wave at the time the snatch occurs. Furthermore, even if the davits are rated for the weight, was the original installation beefed up sufficiently to take the load on the join between hull and davit.

<hr width=100% size=1>

 

[Deleted User YDKXO]

Dont forget that the weight of the boat is supported by two davits not one so each davit supports only half the weight of the dinghy - in theory, anyway, as it is probable the end of the dinghy with the engine on it will impart more load on the davit


<hr width=100% size=1>

 

[stefan]

Thanks for all replies. I did send pics of the davits to Whittall, but they didn't recognize the model so obviously they are Simpson. Must try to locate some ID numbers. Options are to reinforce the base of the davits and maybe use some telescopic pole as an extra support on offshore cruises, as well as change to 5 mm wires. - Problem could be the winch mechanisms that I have wrestled with some in the past.
Probably should have considered more the discussion abt. RIBs that took place at the forum some time ago. The old
345 is performing much better at sea, as the outboard leg have continous thrust even when it is jumpy. The jetrib fall as a stone every time the hull (and pump inlet) is out of the water. Low speed manouvering is nonexistent (no neutral gear) SO IT COULD BE THAT I FORCE SOME UNLUCKY FELLOW TO BUY IT AND STAY HAPPIER WITH THE OLD 345!

<hr width=100% size=1>

 

[Talbot]

of course you are correct when the boat is actually hoisted, there is then a reasonable safety factor (assuming of course the boat has some form of letting water out)

My concern, particularly on a boat like this which has most of its weight towards one end, is that there may well be occasions when hoisting in a bad seaway, that all the weight is jerked onto the one (heavy) end as the boat is being hoisted (seen this happen a lot of times, admittedly with longer and heavier boats).



<hr width=100% size=1>

 

[tripleace]

SIMPSON

I had by simpson davits overhaulled on Tripel ace and they increased the spec of the davits to handle more weight.

Suggest a call to simpsons 01703 631834

They are very helpful

Building 13 shamrock quay,
William street
Southamton
SO14 5QL

<hr width=100% size=1><A target="_blank" HREF=http://www.boating-ads.co.uk/boating-ads/Froggie1.htm> Broom 38 details</A>

 

[Deleted User YDKXO]

Yes, you're absolutely right. Personally, I think the traditional cantilevered type davit is unsuitable for heavy dinghies because the dynamic loadings set up in the wire, davit and mounting must be huge when the boat is bouncing about in a rough sea. Much better IMHO to support the dinghy from the bathing platform and use a crane or passarelle to lift it but, of course you need a fair size platform to do this

<hr width=100% size=1>

 

[stefan]

Re: SIMPSON

Thanks for the hint. I'll try them.

<hr width=100% size=1>

 

[stefan]

Yes I agree. At sea I dont rely on the wires to hold the dinghy but strap it with cargo straps strong enough to alone keep the boat secured. Main concerns are the hull mounting and winch mechanism. - In the future I might consider having a larger platform and crane/passarelle. Need to get the design right to get it light, strong and with the right looks.

<hr width=100% size=1>

 

[stefan]

Anyone able to ID the davit seen on the link below???

Is it a Whittal ED19?
http://arweb.co.uk/aralbums/Boaters2/Davit.jpg

PS. The beer is "Lapin Kulta" brewed in Lapland home of lapdance. Nice lager, served cold not lukewarm like in some odd areas.

<hr width=100% size=1>

 

[Wiggo]

I'd say they're neither Whittall nor Simpson...

<hr width=100% size=1><A target="_blank" HREF=http://homepage.ntlworld.com/graham.wignall/boats/eulimene600x800.jpg>The old and the new</A>

 

[tcm]

um, it is fairly mad to have such a heavy item on the davits, imho. I think you should take it off. Far better to mount on chocks (even cantilevered) on the bathing platform. Busted davits at sea is no joke.

<hr width=100% size=1>

 

[markc]

Deffo NOT ED19 - ED19 have concealed bolts. Simpson do not have hidden bolts, but I agree with Wiggo that these do not look like Simpson

<hr width=100% size=1>http://www.geocities.com/jinto100/Jintopics.html

 

[stefan]

Many thanks for all views. Still appr. an ID. This wasn't the best deal I've made. Jetrib is grounded and old pal Seasport will stay in service for our Holiday trip. We'll see, even if I might extend the platf next winter I probably sell the jetrib. I dont like the performance comp to OB.

<hr width=100% size=1>