towing busted boat with tender

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Meddreamer came on board to verify this experiment and has pix. I'm afraid that the results of this were not great. This was a 200hp jetrib attempting to tow a 36-40 ton (full fuel) 76 foot boat.

Essentially, with tender lashed alongside and towards the stern, it's not easy to tow a planing boat - the tender puls that stern corner around to the other side even if you have full lock towards the tender. Lots of whamming on the bowthruister is only moderately effective.

However, i did eventually get 3 knots and just begin to get some steerage, but it started to go dark. I beleive that i was slightly let down by the dinghy driver who didn't like the smoke coming from "his" tender. Also, a prop-driven tender seems to have better low-speed power whereas a high speed egwhisk/jet rib feels less grunty.

On a sailing boat, there is more steerage at lower speeds - the keel stops the boat being spun around. Also, when i did this on a sailing boat i was desperate (it wasn't an experiment, but real rocks with really-busted engine!) AND it was a charter boat, so we didn't care about gelcoat damagae to big boat nor scuffing the tender - we just wanted to stay of the rocks.

We got the three knots with the tender lashed amidships (NOT at the stern smartypants cliff!) where the tendency for the tender to spin the towed boat is less. It may actually be even better if slightly fwd of the CG, but i didn't have enough time.
 
Mmm. Tried alongside towing a 25 foot-ish fishing boat thingy (like Duncan's floating rum store) last year with the rhino rider (25hp outboard). Mostly managed to go round in circles. Tender lashed to his port side, and could go in a straight line only with full port lock. Situation improved slightly when the dickhead raised the leg (which had been on full starboard lock...)

Tried towing from ahead, to find no steering ability whatsoever.
 
Not tried from the front, can't be much worse really but wd assume need long long line to avoid the dinghy being very nose-down, tho spose jetribs tend to be a bit nose-up anyway unless loaded with people in bows. There's a ski-hook thing on a jetrib so spose that makes a good towing point, otherwise on normal tender obviously NOT the transom.
 
Got back to the boat last year after a BBQ a little bit later than planned to find not an awful lot of water under the keel. Took the tender to the front of the boat, pulled the anchor up into the tender and pulled the boat out 30 metres or so and chucked the anchor back in. Reckon I was doing 2 to 3 knots. Not bad from 2HP pulling 7 ton boat.
 
mm, the articles on towing do recommend using the anchor cos it reduces the tendency to "snatch". I think probably for skankier/larger/sharper anchors, putting a line round the anchor and pulling on that wd be an idea.
 
[ QUOTE ]
on normal tender obviously NOT the transom.

[/ QUOTE ] If it's outboard driven a bridle from the outboard bracket casting would transfer the thrust directly from the source of the thrust, avoiding flimsy transoms etc. In effect the tender would just provide floatation for the motor and driver.
 
Hum, I am beginning to be a bit wary of the towing using the anchor idea now, if it's my boat, and a biggish anchor. With loads of chain out it wd make the dinghy sit even more bows-up. With not much chain out there the possibility of clankity crunch on grp, perhaps.
 
I reckon for towing in calm / harbours that side by side works best.

Couple of weeks ago we took a biggish boat off soft mud using a 15Hp tender getting the stern off using the tender as a tug boat. Tender made fast from the bow to the stern of the stuck craft and used full astern tender power. The skipper meanwhile applied bow thruster at the appropiate moment and the M/E once clear.

For distance towing line astern works best - using the towed crafts anchor cable. Use longish and let the weight of the cable take up 'snatch' as you say. What happens really is that cable pulls the boat along and the towed vessel mearly takes up the slack if you see what I mean....
 
I tried towing with little dinghy once, only round the marina. The dinghy just spins round and is uncontrolable. It worked ok with dinghy going backwards, loads of control this way, but not fast. Easy way is just smash into stern of boat and push it.

Towing from the side requires that the towing boat if tied aft of the towee, but needs to be fairly long to achive this. Hard to do with a dinghy!!
 
Tried the anchor thing before now, too. Once you get a decent length out, the weight of the hanging chain gets too much to hold the rest in the tender, so you either drop it, or hook the anchor into the transom (not good, generally). I'd try a longish, non stretchy rope (otherwise the tender just goes back and forward like it's on a big rubber band), and just give it a fist full with the tender once the rope's gone tight.
 
Very bad idea to use the sky hook designed for towing a skier. The result when trying to tow a very heavy object is that the boat engine drives forward, the high leverage of the hookcauses the bow to rise, and keep rising until it flips the boat - seen it done. You must tow from as low as possible and as near the centre of turning of the tow boat as possible (normally abt 1/3 from stern).

I have towed my cat with a 2hp outboard on a rubber tender secured alongside.
 
different for raggies/cats

as discussed earlier, planing mobos have no steerage at low speeds so alongside will effectively turn the boat in a nice circle until about 3-4 knots by which time boat is probably heading back to the rocks it was originall pointing away from....

On smaller jetrib tenders, the ski hook (er you did mean ski hooks - not sky hooks which don't really exist...) is low down at stern - not on a special "mast" which agreed wd flip the tender backwards.
 
Re: different for raggies/cats

sky·hook or sky-hook
noun.
A helicopter whose fuselage is configured so as to be mounted with a steel line and hook used to lift and transport heavy objects.
or
A hook that is imagined to be suspended from the sky.

Ha
 
Re: different for raggies/cats

this of course begs the question of whether or not a boat can be towed with the aforementioned Sky-hook.
chinook2.jpg

This can carry 12tons underneath it so it shouldn't have any trouble plucking a busted 40footer from the sea and dropping it gracefully back into its berth.
 
Re: different for raggies/cats

Different - not really
More dificult - definitely. The mix of heavier weight and less directional stability (especially if trying to tow an outdrive boat) means that it is much more of a problem. Personally I would not try to tow a much bigger mobo from alongside - similar size yes. but the weight difference between a rib and your boat would be like a flea trying to push start an elephant. I would tow from ahead with some considerable extra weight on the tow cable to improve the angle of the tow and also help directional stability.
 
General comments

Towing using a line forward to a much smaller vessel is hopeless. Until there is some decent forward motion (in relation to amount of thrust applied) most of the energy seems to produce sideways motion and you spend all your time correcting the steering. This subsides only marginally once headway is started.

The size of the line used is relative to the amount of thrust from the towing vessel. Anchor cables etc. are a red herring. A 10mm line is probably enough to transfer the towing effort. There is never going to be enough snatch to damage deck fittings is there.

You might have had better results 'towing' alongside if you got it rotating first, then used the rudders (which then have water flow over them) to straighten her out and get forward motion (see below).

Without a doubt, the best technique is to get the thrust as far aft as possible. Pushing square on the tramsom would be favourite if achievable, offering very good control. Second best is to tow alongside, right aft, with the thrust behind the towed vessel. Not easy with say a 2.5m inflatable, but possible.

Try the dinghy painter led to an aft fairlead, and a breast rope from aft on the dinghy to the same point. On a sail boat (not a modern wide stern one) the dinghy will be pointing outwards, but the thrust is determined by where the outboard is pointing, the hull of the dinghy has little bearing on the directionality of the total rig.

The keel of a modern saily boat offers very little resistance to rotation. Most can be spun on the spot by applying increasing amounts of helm. It's the rudder that offers huge latteral resistance when 'towing' in the prescribed manner.

As per my comments above, control comes quickest if you can allow a sail boat to rotate initially with some rudder sympathetically applied (ie in the direction it wants to turn). Once the water is flowing over the rudder, reducing the amount of rudder quickly brings the rig under control and up to speed.
 
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