Davit Bridle for Soft Bottom Inflatable

[SV Demeter]

Our new to us boat came with a set of Simpson davits. I have a 10' inflateable with a highpressure inflateable floor. I want to keep the dinghy on the davits when we are using the boat. With a RIB there are lifting rings in the floor that allow you to hoist the dinghy up tight to the bottom of the davit arms. This way the tubes of the dinghy are squeezed up against the bottom of the davit arms and the dinghy does not swing around. My inflateable floor dinghy does not have this ability There are rings on the outside of the dinghy near the bow for towing but I am not sure I want to use these for lifting? I was thinking of some sort of strap that could go around the outside of the dinghy but that would not allow me to hoist it up tight to the bottom of the davits. The stern is easy because I can put rings in the inside of the transom. I am afraid if I use some sort of webbing to go around the dinghy it will stretch too much so maybe tubular webbing with dyneema run inside?

[Vasco]

How about adapting this.
Universal Dinghy Lift

[SV Demeter]

Thats basically what I think I am going to have to do. I was just curious as to how others with non-rib inflateables were using their davits. The idea with the simpson davits is that you snug the dinghy up tight to the underside of the davits and the dinghy wont swing around. I will probably not be able to that without a RIB. I could probably do it for the stern but not the bow but I dont want the dinghy to hang bow down as rainwater wont drain. Can I just use the rings on the outside of the dinghy near the bow to hoist with? I use these for towing but did not think they would be okay for lifting. Probably going to go with eyes in the transom and a loop of tunular webbing with dyneema inside for the bow.

[Jim Cate]

G'Day EP,

The bow weight of a 10 foot airfloor isn't much, and a sling made from webbing, fed through the side towing rings for location, whould work just fine, even without the Dyneema. May be a nuisance to rig each time that you hoist, though. Another approach would be to add a pair of aftermarket d-rings with large hypalon patches oriented properly for vertical loading, and then simply use shackles to attach the lifting bridle.

Cheers,

Jim and Ann s/v Insatiable II lying Manly, Qld, Oz

[SV Demeter]

Thanks. I was wondering if I could add some lifting rings to the inside of the dinghy that would be strong enough. Maybe Ill check with the inflateable shop in town and see if they can add the rings? I have now experience gluing these things. Dinghy is PVC not hypalon but we dont leave it out in the sun. It will only live on the davits for time we are out.

[Vasco]

If you do add lifting rings inside the dink put them as low as you can on the tube, then you can snug it right up before you get to block to block.

[osirissail]

The incompatibility of inflatable dinghies and davits versus the RIB (fiberglass or aluminum floors) occurs when the inflatable floor or tubes start to loose air. Then the dinghy's middle sags down to form a "V" with the bow and stern hanging from the davits.
- - A new all-inflatable will last a season without risk of loosing air but shortly thereafter tubes, valves, etc. start to leak.
- - So to hang a pure inflatable from davits I would suggest a long metal tube from which the stern, and bow are hung and also a strap that goes around the mid-section of the dinghy to support that part.
- - As an alternative any form of "sling" that goes completely under the outside of the floor and then outside the tubes in the midsection that can be somehow attached to the davits can be designed.
- - Another alternative is the system where two "tube holders" are attached to a swim platform and the hoisted up to a side-ways vertical position.
- - I found it easier to use the Universal Dinghy Lift and hoist my pure inflatable up on to the foredeck - upside down - for underway storage.
- - Then I went out and purchased an aluminum RIB from AB. That solved the whole problem and greatly increased the utility and comfort of the dinghy experience.

[SV Demeter]

Thanks all. Dropped the dink off this am to have lifting eyes added to transom and inside tubes. Will be making a dyneema lifting bridle. I remioved all the wire cable from the davits and replaced with 3/16 dyneema, I only like to use wire in the electrical system on my boats!

This dinghy is 3 years old and still holds air perfectly. We dont leave it out in the sun. It sees weekender use and gets washed dried and stored below decks after each use. The whole reason we did not get a rib is because we do not live aboard and i did not have a place to store a RIB when not in use (which is most of the time)

We have been very pleased with the performance and durability of this West Marine version of the Zodiak 310 (PVC) with high pressure inflatable floor. We intend to replace it with a RIB when we move aboard and will then have to get a cover made I suppose.

[SV Demeter]

I spliced up a dinghy lifting bridle this weekend from 3/16" dyneema. Was able to get the lift point nearly to the floor so when fully hoisted the floats rest against the bottom of the davit arms and the dinghy is secure with no need for additional straps or lines. The only complaint I have right now is that because we are lifting from so low and from the center the dinghy has a tendency to tilt up to 90* when hoisting or lowering. I keep a boathook handy to prevent this but perhaps the design needs improvement.

[AnchorageGuy]

A word of caution using straps, which we did until we switched to a RIB. The straps will chafe the inflatable in a very short period of time, and seriously if you travel any distance with it in the straps. We had to add patches where ever the straps came in contact with the dinghy.

[osirissail]

There is no "rule" that you can only use one line to each attachment point. You could also have an attachment point on the outside of the tube that connects to the same point that the inside line attachs. The additional line would keep the tubes from dropping to the vertical. In other words each attachment on the aft end of the dinghy would consist of a pair of lines, one attached inside and the other on the outside of the tube.

[SV Demeter]

Waterway guy I have no intention of using straps, that was the whole point of setting the bridle low and inside the dinghy. This allows us to pin the floats to the bottom of the davit arms. Simpson davits with rubber pads on the underside of the arms.

osirissail I think I follow your suggestion. There are a set of rings near the bow on the outside for towing. We added rings on the inside for lifting. If I ran line from the outside rings in to the hoisting line that would keep the dinghy from beign able to tip? Let me think about that one for a bit.

Thanks,

[osirissail]

Waterway's excellent chafe reminder also applies to rubbing between the davits and the dinghy. I have seem cruisers with all sorts of material stuffed between the davit arms and the dinghy to try to transfer the constant movement (albeit small) between the davit arms and the dinghy tubes. I think that perhaps a rod or bar/tube from the dinghy transom to the davit arm might be able to immobilize the movement such that the tubes are not up against the davit arms might work.

[SV Demeter]

Ill keep that in mind although for next few years we wont likely be on any long passages as we have a lot of refit work to get done. Probably going to a rib when we move aboard and will need to address the chafe issue I am sure. For now we dont leave the dinghy on the davits full time as we dont have a cover and prefer to store the dinghy below decks in a bag.