Towing a RIB

We occasionally tow a 15’ rib behind the 116 i run, especially for short hops in the Exumas. It has a pair of towing brackets and I use a bridle tied to a heavy dock line. On short hops we never go above 11kts though. Usually we keep the engine slightly dragging in the water. When anchoring I have a crew shorten up the tow line. When docking we drop it and one of the crew hover while we dock.

But usually we just bring it back on the platform. Easier

Make sure to use backing plates on the tow point(s).

I prefer to tow with the engine down, as it creates a bit of drag if the tender is surfing following seas. Just remember that the lower unit will be spinning, so any time towed should be treated as running time for preventative maintenance purposes.

A high water alarm is the safest thing. Perhaps check out Siren Marine, which is sold was West Marine and works to an app on your phone.

In the past when single/double handing while towing, we would pull the tender onto the hip of the mother ship (obviously on the opposite side of the dock when alongside).

I must ask this question. You normally store it on your upper deck. Is it really easier then to tow it and deal with it that way than just to put it in it's normal home? I understand towing when the other boat is too big to put up top or on the platform, but we take our RIB's down and put them up all the time and don't find it to be that much work. Perhaps something to simplify storing it up top or even a setup to carry it on your swim platform. Is your 60 a Convertible or Motor Yacht?

We carry an 11.5 Zodiac on our foredeck to use for short cruises in local PNW waters. However when we go north to Desolation Sound, the Broughtons and beyond for weeks at a time we put the Zodiac on the hard and tow an 18 Novurania. For both RIBs we had tow points with backing plates installed and proper tow bridles made. Towing length is important. We want the RIB to ride at a particular place in the wake. Sea conditions permitting we will tow at 21 kts.

For tow rig geometry toweye.com is a site with helpful info. To measure the appropriate tow length, tow a buoy/fender on a long polypropylene line to determine where you want the tender to ride in your wake.

We tow with the outboard up. Our tow rig angle has the outboard’s skeg trailing enough to keep the tender from skating from side to side in the wake. I’ve made a rig to secure the Zodiac’s outboard centered, preventing it from flopping to one side. The Novurania doesn’t need it.

To make it easy to watch our tow from the fly bridge helm we have a water ski rear view mirror mounted on the underside of the fly bridge roof. Frequent glances at the mirror are far easier than us turning to look, especially on long runs.

Docking at marinas one of us will hover in the tender while the other docks the boat. Manoeuvring in close quarters is easier without the drag of a tender secured alongside. Later the tender can be secured alongside (fairway room permitting) or we tie it up at the dinghy dock. Reverse the procedure on departure.

Anchoring is easy. Just secure alongside.

Rafting inside two other boats, something we do frequently, requires a rig involving dock mooring whips to keep the tender aligned directly behind the swim grid.

I've towed various RIBs to 15' and a 25' all fiberglass center console in many areas, including Alaska, Pacific Northwest, Mexico, Caribbean, and the entire Eastern seaboard with nothing more exotic than 3/4" polypropylene 3-strand. It floats, it's shock absorbing, and easy to splice. Comes in Hi-Vis colors! The first one I made got backed over and parted three times. A long-splice and the thing was repaired. The owner wanted me to replace the tow line with a new one, as he wasn't proud of the three long-splices He couldn't remember to let the crew clear the tow.
Some of the benefits of a floating line is that it's lighter to manhandle, and it won't sink and draw the tow to the yacht.
The most important thing to design in is a short painter that isn't removed from the tow, rather the tow line is clipped to the painter. It's dangerous trying to release a tow at the bow eye. Could end up with a broken arm.
I've also towed a larger center console from Puerto Vallarta to Bocas del Toro, Panama and then Galveston with a Spectra professionally made towing harness with dock line outer plait covering the Spectra. It was a good bridle.

I don't know if you are correct about it absorbing shock. While poly does stretch, it's more a creeping stretch than elastic (like nylon).
For short tows, I wouldn't have any issue with using strictly poly but for longer tows, across potentially rougher seas, I would recommend a combination of poly and nylon. The nylon could even be a pendant that stays with the RIB and connects to the poly.
Without anything to absorb the shock of pounding seas, you risk damage to your towing gear.

It will depend upon your boat’s wake and how your RIB tracks at the speeds you tow. Your RIB may ride better behind the second or third wake wave.

I think that when you see what your wake looks like you’ll be able to identify the sweet spot. It may be behind the first, second or perhaps third wake wave. Towing a fender will allow you to measure the length to that spot. Took me one run to figure it out. Good luck!

To be honest, based on how (I think) you will be towing, you are probably putting too much thought into this. That being said, if I had one chance to choose where I plan to tow, I would get the boat to cruising speed and then find the length (the fender is a good trick) at which the end of the tow line is just aft of the second wave. This will have the tender essentially climbing the second wave perpetually, which will reduce the risk of surfing down following seas. I've used this method several times, and haven't had to revisit the length.

Ken Bracewell nailed it, adding a detail that I should have included. His description is exactly how I tow.

Listen to Ken, he knows what he's talking about.