How do you secure an inflatable RIB in davits?

Rivers & creeks

Rivers & creeks

Well-Known Member
Joined
23 Nov 2004
Messages
10,924
Location
Norfolk
Visit site
We have a 3.4m soft bottom RIB weighing in at 48Kg and outboard at 30Kg. The stern is no problem with two eye bolts but I really don't fancy that lot being held by two stick on patches at the bow or using the lifting handle. I had the mad idea of running a webbing strop underneath at the bow and up through the lifting handles to stop it slipping. Silly idea? Should I trust stick on patches?

A dumb question about loads - is the weight held evenly by both davits or is the extra weight aft held disproportionally by the stern davit?

Advice and ideas welcome :)
 
Last edited:
Surely a "soft-bottom RIB" is an inflatable? :)

A strap from the tip of the davit arm, under the dinghy, and back up to the davit seems like a seamanlike stowage arrangement to me.

If the aft end of the dinghy is heavier, then obviously the davit closer to its stern will be carrying more weight.

Pete
 
Going to be on the stern of the new RIB when on hols. Rest of the time on the bracket to take weight off the RIB - we can use the davits to lift it.
 
I take it it is not a RIB and therefore has no rigid floor in which to put eye bolts. FWIW I had the same problem with the previous inflatable and glued two lifting rings low down on the inside of the bow. Was ok for the five years I used it. You can get them from Polyfibre. Edit, that's Polymarine - linky:

http://polymarineshop.com/triangular-d-ring-patch.html
 
Last edited:
Hadenough said:
I take it it is not a RIB and therefore has no rigid floor in which to put eye bolts. FWIW I had the same problem with the previous inflatable and glued two lifting rings low down on the inside of the bow. Was ok for the five years I used it. You can get them from Polyfibre. Edit, that's Polymarine - linky:

http://polymarineshop.com/triangular-d-ring-patch.html
Click to expand...

Thanks for that. Yes, inflatable bottom - SeaPro 340HD. It does worry me that it's taking a fair chunk of the 80kg. Glued lifting rings?
 
Lazy Kipper said:
Thanks for that. Yes, inflatable bottom - SeaPro 340HD. It does worry me that it's taking a fair chunk of the 80kg. Glued lifting rings?
Click to expand...

Yes, that is the recognised way of doing it it you have not got a solid bottom to screw an eye into. Make sure you get the correct type sand adhesive for your boat. If you think about it, the towing ring is on a glued on patch and that potentially takes far greater loads than hanging off the davits. You might attach a security wire to the towing eye, or just use the painter as extra security should your patches fail (unlikelY0.
 
Lazy Kipper said:
Thanks for that. Yes, inflatable bottom - SeaPro 340HD. It does worry me that it's taking a fair chunk of the 80kg. Glued lifting rings?
Click to expand...

A guess but from my recent experience of beefing my davits up to take a heavier outboard I'd say that in your case the bow davit will be taking about 30kg of your total 80. Thing is not to get tempted to use it as the shed! Don't worry about the glued on lifting rings, as long as you make a good job with the right glue it'll take it.
 
Lazy Kipper said:
We have a 3.4m soft bottom RIB weighing in at 48Kg and outboard at 30Kg. The stern is no problem with two eye bolts but I really don't fancy that lot being held by two stick on patches at the bow or using the lifting handle. I had the mad idea of running a webbing strop underneath at the bow and up through the lifting handles to stop it slipping. Silly idea? Should I trust stick on patches?

A dumb question about loads - is the weight held evenly by both davits or is the extra weight aft held disproportionally by the stern davit?

Advice and ideas welcome :)
Click to expand...

Hi Simon

Here you go on a CW 34'-6" AC and happy Christmas!

View attachment 47825

Mike
 
Last edited:
Wow - great photo. How does he stop the forward strop from sliding off the bow as it gets narrower I wonder? Very jealous of his aft portholes :cool: he seems to have a different aft deck to us.

Happy Christmas to you Mike.
 
A really interesting question - which I am afraid I never solved.

I purchased the same type of tender. The main reason was because I had a weight restriction on the davits and thought the rigid floored tenders with the outboard would be too heavy. Unfortunately it was a major mistake. I ran a line from the transon to a heavy duty attachement point already on the inside front of the tender. That sort of worked but the line lifted too much which prevented the tender lifting snuggly against the davits. I then fitted heavy duty patches on the inside of each tube. That was a lot better. It is essential to position them as low as possible. However I was never really happy with the solution. There were signs of the patches pulling off and I was worried about the effect of the tender filling with water. In the end I am afraid I replaced the tender with a Ribeye which is amazingly light, in fact almost the same weight. I then drilled through the floor and fitted robust eyes. Even the rigging was an interesting challenge. If you put the engine on the tender it is totally evident how much of the weight is displaced towards the rear, so in my case it was vital the rear lift point was just forward of the engine. The transom isnt quite the solution because the davit wire then interferes with the engine when this is left on the transom. The long and short is rigging the tender for the davits is really surprisingly important especially if you want to ensure an even lift, that it will fit snug against the davits when at sea so it doesnt move around, and yet the transom can be left lowered a little in dock to allow water to drain. The final element is to rig straps to secure the tender beneath just in case at sea the davit wires give way!

The last bit of my puzzle was a solution to lifting the engine from the rear rail onto the tender. That solution I think I have just solved and am looking forward to trying it. I found lifting a 15 HP engine onto the transom no fun at all and only just manageable. With heavier engines it is an important consideration I think because I dont think you want the engine left on the transom in the event of more challenging weather.
 
Lazy Kipper said:
Wow - great photo. How does he stop the forward strop from sliding off the bow as it gets narrower I wonder? Very jealous of his aft portholes :cool: he seems to have a different aft deck to us.

Happy Christmas to you Mike.
Click to expand...

Because the aft and bow strops are tied together below, when lowered into the water the bow/aft strops are loosened and all is released!
 
We have a small rib on davits. 3 lifting eyes mounted on the fibreglass bottom make it relatively straightforward to lift, which I realise doesn't help the OP very much.

However, one thing I would say is that we *never* lift the dinghy onto the davits with the outboard on the transom - just too much weight not balanced properly and I hate to think what loads would be generated in any kind of seaway. We have a separate engine crane (not expensive) next to the davits with a 6:1 tackle and a pad mounted to the stern rail to sit the outboard on. It's a bit of faff to lift on and off but not too bad once you get into the swing of it, so to speak. Engine is a 10HP Tohatsu 4-stroke.

For a non-rib inflatable dinghy I'd suggest the first thing to do is have an arrangement for storing the outboard separately, which will eliminate a whole world of stress and make tube-moounted lifting eyes more feasible.

All IMHO, YMMV etc etc
 
ip485 said:
A really interesting question - which I am afraid I never solved.
Click to expand...

butbutbutbut....

You have an IP485 - it has a dinghy crane built into the outboard end of the boom. And you have half an acre of clear flat deck at the stern. Shorely you just heave it all up with the boom using one of the many electric winches available and lash it down somewhere? :)

The last bit of my puzzle was a solution to lifting the engine from the rear rail onto the tender. That solution I think I have just solved and am looking forward to trying it. I found lifting a 15 HP engine onto the transom no fun at all and only just manageable. With heavier engines it is an important consideration I think because I dont think you want the engine left on the transom in the event of more challenging weather.
Click to expand...

This one: http://www.katomarine.com/outboard-katolift.htm
 
Lazy Kipper said:
Looking again at the photo Mike, is it definitely a 34? It's a really interesting shaped one, did they use different mouldings?
Click to expand...

Hi Simon

Yes she is a CW but one of the Narvik 35 class (still based on a CW 34'-6" hull as yours), I have other photo's of her if interested as she also has a huge bowsprit,e-mail me if interested.
 
Saguday said:
butbutbutbut....

You have an IP485 - it has a dinghy crane built into the outboard end of the boom. And you have half an acre of clear flat deck at the stern. Shorely you just heave it all up with the boom using one of the many electric winches available and lash it down somewhere? :)

I know. There are just a few features I dont like. One is the boom crane. Sounds good in theory but the dinghy needs to be lifted over the side, not transom. Securing the dinghy on the rear deck means adding some stringers and of course not really possible with the engine attached. Then you cant get at the lazarette, gas bottles or scuba compressor. On the other hand for lifting things on board from finger pontoons - its quite useful.

There is no solution quite like davits. If the engine crane in the solar arch works it might be the perfect solution.
Click to expand...
 
You must log in or register to reply here.

Share this page

Top