How should I safely tow an inflatable?

[SailorT]

I'm considering buying and inflatable, soft, or maybe a rib. Leaning more toward a rib. I'm a little concerned about towing it. I have a 39' sailboat with no deck space. Does any one have any advice around towing a inflatable/rib? What heavy air conditions and following sea? Do they tow ok in this heavy stuff? Does a cover over the inflatable help any with water getting in the boat from wave slopping over the side? How heavy do they really tow? What about towing them with the motor attached. Does the the motor cause additional towing headaches? Any towing advice would be greatly appreciated.

 

[snowleopard]

In a sea, an inflatable can easily flip. Carrying the motor on the back slightly reduces the risk but ups the stakes. I once lost an outboard that way. A rib will be a lot safer as its weight and hull form will keep it in the water longer.

If you must tow, keeping the painter short, even to the extent of lifting the bows out of the water, seems to help. If you have a non-return drain valve in the transom, leave the bung out.

 

[dralex]

Towing a dinghy can take at least 1/2 knot of your boat speed. If you have to, make sure you rig a towing bridle from the d rings at the bow- this spreads the load to a single line. ANother way which works quite well is to use two lines, one from each d ring at the bow led to each aft cleat. This gived the tow more stability, but can get a bit out of balance if you are heeled and the lines are short.
DO you not have a largish locker on a 39 footer that you can stow a deflated dinghy, perhaps with inflatable floor. FWIT, I never tow with the outboard on unless it's a short flat water trip.

 

[SailorT]

Sounds like good advice. Would a cover help keep the water out? If an inflatable doesn't have a transom drain, do you know if there is an after market way to put one in? When you pull the inflatable up to the transom, if the motor is on the back doesn't lifting the bow cause the transom to almost get submerged.

 

[homa]

Hi SailorT,
I have towed a rib with outboard in moderate to rough seas in the Caribbean when chartering with little problem.
The rib tends to have a low C of G, though is quite heavy and you definitely loose speed when towing. If the weather forecast was that bad would consider humping the outboard onboard the mother vessel.
Kept painter at about 20'.
With wind & following seas dinghy does tend to overtake mother vessel. Best to shorten painter in these conditions to avoid dinghy overtaking or veering off and risk capsize, though unlikely. All painters that I saw on other ribs tended to be attached low down near water line so less chance of a capsize.
If you can live with the heavy weight and loss of sailing performance when towing then I'd recommend the rib every time.

 

[SailorT]

Yeh, I could stow a soft inflatable in a locker, but I don't have a locker big enough for a RIB. Like the idea of the double line.

 

[SailorT]

Glad to hear you would go with the RIB. I really think the soft inflatable is best for stowing, but the RIB is better for planning out and beaching. Now I wonder if a RIB tows harder, then a soft inflatable? Or does the hard bottom really make the towing easier.

Could you explain why the towing attachment being low would help reduce the broaching the boat as the dinghy surfs toward the mother ship. I kind of thought if the dinghy got out there sideways to the mother ship the wave would cause the boat to flip regardless of where the tow attachment was. Please correct me so I understand.

 

[muchy_]

The only problem with leaving the motor on is that it can work loose and drop off. Don't leave it in the water, always tilt it forward and tie a short lenght of rope on it so if it does come off you wont loose it.

 

[john_morris_uk]

The modern design of inflatable with one of these new inflatable floors and inflatable keels plane pretty easily. They also stow away very nicely as well.

No one has suggested Davits yet. Lots of small RIBs stow very well on Davits, and its a bit more secure than leaving them alongside.

I can't imagine towing a tender continuously and even in 25 footers there's usually a space somewhere to stow an inflatable.

 

[homa]

I'm no expert on RIBs, and have only towed a rigid inflatable when chartering.
Probably 4 weeks in total.
At home I have towed a rigid Tepco (all GRP, smoothe flat bottom with stubby keel)and more recently an 11' fibreglass simulated clinker dinghy.
The latter is quite heavy and a good load carrier and stable, but it does tend to track in a straight line and will overtake in a following sea or when slowing down quickly. Its painter is attached near the gunwale, so when the weight comes on suddenly from the side, there is a tendency for the dinghy to roll towards the direction of pull. As my boat has a relatively low freeboard the angle of pull is nearly horizontal.
On holiday with the RIB, the towing eye was at water level, so when RIB overtook us, the weight come on, and had a tendency to lift the RIBs bow upwards and sideways. With resulting less capsize moment. Plus of course a RIB is that much more stable anyway.
The RIB was so heavy it lost speed pretty quickly as it tried to overtake. It was the waves that tended to push it along rather than the wind compared to towing a pure inflatable.
Have towed these (inflatables) and they're a nightmare in windy conditions, Only thing is to partially deflate and stow on deck.
Ideally I would not tow at sea, but if I have to I have always rigged 2 painters, have seen a couple of dinghies come adrift over the years due to chafe of the painter.
When in the Caribbean, a lot of yachts towed their RIBs. I never heard of one being capsized, though some were "lost" due to pure negligence of the charterer.
One final note, the one thing I didn't like about the RIB was its weight, ours were really are heavy and almost impossible to drag up a sandy beach single handed. It may be that they were over built for the rough charter market.
To my cost, half way through our first holiday realised there was a loose keel plug, so the RIB keel had filled with sea water, once drained it was easier to pull, and boat speed noticably improved !

 

[ghost]

further to Alex's brief......
A dinghy can take up to a knot off overall boat speed,
but if you have to you have to.
Suggest a double bridle 'tho, that is, two towing warps and a rubber shock absorber with the two lines through it, length of tow warp is dependant on conditions and type of dinghy. Alternatively, keep a small inflatable such as a waveline or wetline deflated and rolled but ready below, even the smaller versions easily take a 3 - 5hp engine and can be inflated in six / seven minutes, avoiding the stress of towing and shiftable ballast below. remember to depict the mother boats name on the dinghy.
if you tow it with its bung out, any water taken on will fairly quickly 'fall out ' the hole at the dinghy transom. A few dinghies' have snapped thier lines when sudden ingress has increased the strain on the warp and continued hauling through lumpy sea has been too much for the warp and snap crackle .....pop..

 

[Guest]

Until the dinghy flips over when the wind blows.

 

[Mudplugger]

until the tow line pads (both) come unstuck! about F4-5....Live & learn.

 

[Rabbie]

If you rig a towing bridle - beware of chafe - as I have just found out to my cost!.

 

[saylor]

Has anyone used a Porta-bote as a tender? The manufacturers claim quick assembly and easy (flat) storage. They also only need small (max 9hp) outboards.

 

[homa]

Just come accross an article on just this subject.

PBO (no. 458) Feb 2005 p 102-3

Written by a chap who has towed an inflatable over 30,000 miles.

Includes how to tow a rib in rough seas.

In summing up he recommends leaving outboard connected and a tight fitting dinghy cover