Lines for davits and towing

[bearkeley]

Just purchased a new 9ft RIB with a 10hp engine and St Croix Davits...now it’s time to select the lines. St Croix sells specific lifting lines 5/16 double braid, but doesn’t specify if it’s nylon or poly or any other info. Sounds like the wrong lines can cause havoc in the future so wondering what the group suggests for the following:

Davit lines...would any 5/16 work?

Sling....should I buy wire or other sling or would the same type of davit line work?

Towing....planning to simply get floating line....or are there a million different kinds too?

Hoping to leave for our first trip south in a couple of weeks so any advice would be appreciated. Thanks!

[Vasco]

For the lifting lines get low stretch double braid that fits the sheaves of the blocks. You do not mention which blocks you are using. It's best to have triple sheaves on the outboard end and double on the bow end of the dink.

For the lifting harness it depends on where the attachment points are on the dink. Two points on the low part of the transom and two at the bow is best. Many dinks only have one at the bow. When I had an AB which only came with one bow attachment point I put two D rings in the floor close to the bow. Get a rigger to make wire slings with ss hooks. The slings are shackled to the falls and clip onto the dink

As for towing any line will do.

And you will need a chain or ss wire and a lock for locking your dink when you're ashore in certain ports (most of US).

[UNCIVILIZED]

Were it me, I'd be tempted to use a single braid dacron for the lifting lines in the blocks. That way you can't wind up in a situation where the cover & the core have different amounts of twist in them. Regatta Braid has a nice hand (feel) to it, & 3/8" is about the smallest you want to go if you'll at all be pulling on it by hand. As smaller diameters than this are difficult to grasp.

For lifting bridles, go with spectra. It's easy to splice, long wearing, & it'll never grow any meat hooks like wire will. And it's easy to luggage tag any sort of shackle or hook onto spectra.

One thing to consider is adding 2 eyes for lifting in the bow. And you can even bond in some pieces of G-10 to the hard floor of the RIB, & put padeyes onto said pads by epoxy bonding the fasteners into the pads.
Or if you do a lot of diving & other excursions in the dink, sometimes it's nice to add sections of slotted toerail track to the dink's floor, so that you can lash gear in place. And you can also attach the lifting hooks to the track.

In terms of towing line, floating is nice. And there are several lines purpose designed for this. Many of them in the Defender catalog. Avoid going with a line that's purely polypro, as they die quickly from UV. But the stuff makes tolerable covers on other floating lines.

[savoir]

You don't need anything fancy. Any brand of 5/16" fuzzy will do. Fuzzy works better with wet hands.

[fatherchronica]

Whatever else you do, do not back over the towlines when entering a slip or setting your anchor. And always have a wetsuit aboard if you tow.

[skipgundlach]

Originally Posted by UNCIVILIZED

Were it me, I'd be tempted to use a single braid dacron for the lifting lines in the blocks. That way you can't wind up in a situation where the cover & the core have different amounts of twist in them. Regatta Braid has a nice hand (feel) to it, & 3/8" is about the smallest you want to go if you'll at all be pulling on it by hand. As smaller diameters than this are difficult to grasp.

clip...

I have Regatta braid for both my davits and genoa sheet (different sizes, of course).

The davits, run through a double and a double with becket, have significant twist in the line despite all my efforts to remove it.

The result is numerous block rotations on the front, and several on the rear, before they lead fair under load.

Awesome hand (soft), but not so great for running through multiple block turns.

Except that it's so expensive to remedy, I'd go with double braid - something like stay set, or the one below that in stiffness, currently unremembered...

I pretty much agree with the rest of the comments; if you can double your pull on the sides (not a single center point) you'll have more stability.

L8R

Skip

[UNCIVILIZED]

Hmm, interesting about the Regatta Braid. It's great on main sheets, even on 6:1 or better purchase systems. Maybe the issue with it & davits has to do with how close the blocks get to one another.

As to double braids, Samson makes a few different grades of it. And for those who need them, Harken has diagrams on how to best reeve the lines in tackles so that you get the least friction & snarls Harken Sailboat Hardware and Accessories

Edit: Bruce Bingham's The Sailor's Sketchbook has some excellent tips on towing dinks, & other tips on dinks as well. Plus a plethora of other useful ideas.

One tip about towing dinks is that quite often it's wise to put a large padeye in each corner of the dink's transom, on the inside of the boat, facing forwards. And to then rig a bridle from these, through a bow eye. It helps to stabilize the dink, much like a multihull's anchor bridle, & also keep the dinghy in a bow up attitude.

You also want a bit of elasticity built into your towing system, to help with easing shock loads on the dink when encountering waves & such. Speaking of which, it's not uncommon to have D-rings that are held onto dinks with swatches of glued on fabric pull off under towing loads.

[SteveSadler]

I don't use davits but they are convenient. I hoist my 12' Rib with Honda 20 on, with a spin halyard, and set it on the foredeck, for long passages. For just an overnighter I tow it 5' behind with a dockline, rubber snubber, all in a pvc pipe to a cleat on the transom.
The 5/8" braided poly painter with spliced eyes and a heavy carabiner is attached to a separate cleat as a safety only. When I hear that click, I know it will be there in the morning.
The towing setup addresses all possible problems of towing.
The painter or tow line can't reach the prop.
The dingy can't surf into the transom as the pvc holds it off.
When caught is a squall, it can't launch off a wave and flip when wind gets under it.
Its close enough to surf the stern wave for minimum drag
it should also be towed from a very low point so wind doesn't get under it.
The engine is left down for straight tracking.
Its always in our smooth wake, no pounding.
In extreme dead downwind surfing conditions I'll tie a long dockline around the towline,
and toss it in our wake. This creates enough drag to keep it from surfing too much.
The most common problem is wind getting under the dingy and flipping it, I've even seen it happen at anchor in a squall!

[bearkeley]

Thanks for the great info. Fortunately, the davits come with 9:1 purchase. Helpful insight re: towing and lifting on two vs single point. Not sure what my RIB (Highfield) has so need to check.

Not sure I understand the comment re:wetsuit though.

[savoir]

Highfield have two lifting points at each end. They are on the floor. You should add a thimble to the bottom end of each sling to reduce chafe.

[Bulawayo]

Some interesting responses. I use 10mm ex-climbing rope. Yes, it has some stretch in it - which I really like as in bouncing weather it allows shock absorbing rather than transfer to the davits /or dinghy points. I dont understand why anyone would say no stretch. Im fortunate that my dinghy sits on the aft platform.

Originally Posted by bearkeley

Just purchased a new 9ft RIB with a 10hp engine and St Croix Davits...now it’s time to select the lines. St Croix sells specific lifting lines 5/16 double braid, but doesn’t specify if it’s nylon or poly or any other info. Sounds like the wrong lines can cause havoc in the future so wondering what the group suggests for the following:

Davit lines...would any 5/16 work?

Sling....should I buy wire or other sling or would the same type of davit line work?

Towing....planning to simply get floating line....or are there a million different kinds too?

Hoping to leave for our first trip south in a couple of weeks so any advice would be appreciated. Thanks!

[doublewide]

Agree with other comments and have a couple of suggestions, to wit:For the falls, use best-quality doublebraid dacron line
For the slings use Spectra or equivalent with four widely spaced attachment points on the dinghy, and a metal thimble at the apex of the inverted "V" shaped slings.
Offshore we never rely on the falls to keep the dinghy secure, but we add a stout relieving line from the slings to the arch/davits, just for the day when the lifting block explodes mid-passage. When the block fails it will be in big seas, and that is not the time you want to stop to recover the dinghy.
And you must always secure your dink fore and aft and laterally so it can't wiggle even a millimeter. Buy yourself some stainless steel ratcheting cargo straps and 316 stainless hooks or whatever hardware you need to quickly hook up and strap the dinghy tight against the transom.

[Cheechako]

I used low stretch sail/sheet Dacron line. I went to 3/8 for ease of the hands. I had some old, but nice, line with the soft fuzzy cover on it which is even more hand friendly. How many part tackle will you use? It doesnt need to be super low stretch though. Buy your blocks and let that define the line size, bigger the better.

[savoir]

If anyone needs davit lines Defender have Trophy braid on sale this week. 5/16" is only 61c/foot which is less than half the price of Sta-Set at Westmarine.

[Privilege]

I'm with Uncivilized and others on choosing dyneema/spectra for the lifting slings. I got my 1/4 dyneema from eBay at $15 for 50'. It doesn't scratch or mark your dink, even for a novice it's super easy to splice and once you've done it, you'll never want to splice double braid again.

I was thankful for that decision a couple of months ago when I raised the dink on the davits and forgot to remove the drain plug. With heavy rain overnight, the 10' dink was two thirds full when I discovered my mistake. Fortunately, the dyneema and davits held it without drama.