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View Full Version : Can anyone tell me about towing an inflateable dinghy?



PatCox
05-29-2005, 09:06 PM
My "new" boat is a 34 foot Mainship trawler, vintage 1982. Top speed, 13 knots, average cruise, less than 9. I have a 10 foot inflateble with a 10 horse yamaha. It should be as fun as a jetskeet, without the guilt. But I seriously need that little adventure boat to get off to the shallows where I love to clam and crab and try to live off the land (water) for a weekend at a time.

But I am going to have to tow it, its just a hair too big and heavy to haul aboard.

What do you do, at 10 knots, tow it at some length behind the boat, or haul the bow right in behind the stern, as I see some do? Any pointers would be appreciated.

[ 05-29-2005, 10:07 PM: Message edited by: PatCox ]

seafox
05-29-2005, 09:15 PM
I think your bigest worry is that your atachment point be strong enough and maybe have a back up atachment point when the first wears through

as for length of towing line go out and speed up to your general cruse speed and their will be a hump where the water comes back together a bit bacl of your boat at that speed. you want the towed boat to be on the forward slope so that it surfs alter you with less strain. the worst place is just a bit farther back where it would be trying to climb that hump the middling choice it to have it abouther boat length back so that it rides in the flat water beyond the hump
just my opinion

one other sinsideration is that their might be more turbolance rifing in front of the hump that would lead to stress on the line and ankorage that would argue for having the inflatable follow in the flat water beyond the hump

High C
05-29-2005, 09:35 PM
Jeffery's advice is sound, and use a line that floats! Line in the wheel can ruin your day!

paladin
05-29-2005, 09:37 PM
the strongest point will be the transom...normally lines are attached to eyes in the transom and led foreward thru fairleads, then to a bridle arrangement to take the towing stress off the glued on attachement points on the dink..also the towing line should be about 3 wavelengths aft. You will need a cover on the dink, and strong safety lines on the outboard to secure it to the dink.....

J. Dillon
05-29-2005, 10:13 PM
Pat, I wouldn't consider towing it at all where conditions might make for following seas.

In one experience I had taking a 34' sail boat down from Wilmington NC to Cape Fear and beyond, we had a following wind and towing a Zodiac maybe about 10'long or so. The wind and current were opposed building a short steep waves. They were breaking aboard the Zodiac. No matter where or how long the length of the tow the waves broke aboard. It kept taking on water to the point it was slowing us and effecing our steering considerably. Even with just the jib set we could not pull that boat up to bail the water out. Finally the situation got deperate where the line might break or the cleats pull out or something give, so we pulled over to the nearest harbor I forget just where. I know a ferry ran in there so we had to time our arrival to get in just after the ferry left. Then we were able to pull her up and bail her out and get it aboard.

With a boat like your's why not pull it up on the swim platform when conditions might get "nasty" or better yet aboard?

Even with weather forecasts peering into the future, things change pretty fast.

JD

Ian McColgin
05-30-2005, 07:21 AM
People round here tow at those speeds and higher no problem. Four points to success -

Bridle, as well pointed out. Nothing worse than someone coming on deck, looking about searchingly, and musing, "I wonder what happened to that little boat that was following us."

Get the motor off. Gas tank and loose junk as well. Make a rail mount on your big boat for that motor, create a sling and maybe even a little derrick if you need an assist, but try not to tow with the motor on the dink. Slows everying up, adds mass and hassel, may damage either tender or motor.

Tow up nice and short. Local displacement boats (typically cruising about 15 kt or less but a few run at 20 kt) snub the tender hard against the transom bow a bit above the waterline. If they have a swim platform, the bow rides up above it.

At displacement cruising speed this leaves only the last bit of the tender riding the slope of the wake. Efficient. And the dink can't come flying forward to his the transom, maybe making a nice loop in the tow line to foul in a prop.

Won't work with outboards or outdrives, of course.

Finally, assuming you're towing short, leave the drain in the transom open. Spray can then go out. There are inflatables with no drain provision. I've seen them towed fast snubbed up against the transom, maybe higher than you otherwise might. The water that's trapped near the stern is not enough to hurt things much.

Gary E
05-30-2005, 07:38 AM
Ian has some good ideas for towing. If I understand your intent is to drag it around in the back waters of the NJ intercoastal, if so then you can use just about any string or rope, do not leave it to far aft of you or the jetski guys will play jump rope with you. If your boat is gas no problem but if it's diesel, buy your favorite cleaner and rags by the case. If towing it off shore is the intent, think about the trip you just made, do you really want to fool with towing one? not me, get it aboard.

Figment
05-30-2005, 08:04 AM
Does the mothership have a swim platform?

Weaver Snap Davits are just the thing. We just installed some on my father's boat because he and my mother are getting beyond the point of wrestling the thing over the gun'l. We should've installed them YEARS ago. The word "convenience" is not sufficient.

That '82 Mainship 34 is the same hull as the Silverton 34 and the Luhrs 34, right? If memory serves, the overall beam is something like 11'6", with almost 10' at the transom, so you might just be able to make it work.

Ian McColgin
05-30-2005, 08:08 AM
And I do mean hard on the transom. You may want to sew up a turkish towel material bad that will fit snugly and stay in place over the inflatable's bow to reduce chafe on the inflatable and marring on the trawler transom.

The bridle lines can be led together and up over to a quarter cleat on one side of the transom if you've a single exhaust to get the tender away from. If you've exhausts down on each side, pull her up the center of the transom. She'll have the bow above your exhaust ports anyway.

When you're running at cruising speed the bridle will let the tender hang back an inch or so off the transom. Just don't let it get so sloppy that it can bump hard as you slither over small following chop.

Depending on the shape of your transom and cleat location, chafe may be an issue. You'll want some metal half round or something protecting the top edge of the transom and you probably should have some chafe guard on the pendant where it comes over the transom.

Once you have this rigged and are happy with how to handle the OB on and off, you should have no trouble running pretty near any place in the weather you want to move about in anyway.

Thinking of the OB - The make or you could make up a little drop in derrick. Or be really shippy and have a gin pole on the boat for lots of occasions. If you're anchored in an open area, there's nothing worse than trying to balance and stand up with OB in one hand to hand up to someone on the trawler while bouncing about. If you have a little derrick, you can hook the motor with a sling, take a little strain, unscrew the motor and swing her up out of the way. Belay that and let it dangle while you scamper aboard the trawler. Easy, safe and no dropped OB.

You're cruising. Make each step easy.

G'luck

PatCox
05-31-2005, 01:55 PM
Thanks to all, especially Ian. I will be doing this only for a weekend at a time, only in the bay. I would try those weaver davits, but its just one more of about 100 expenses I am trying to avoid.

Rigging a hoist for the engine does sound very worthwhile, its a four-stroke and weighs 100 pounds. Thats going to take some thinking through, I think. The boat has an extended flying bridge that covers half of the cockpit, and the back of the flying bridge is held up by two stainless pipes, running from the back of the bridge down to the gunwhale. It seems a simple solution would be to use this as the vertical component for a derrick, the arm could be another piece of the same stainless pipe, attached down at the gunwhale with a gooseneck, with a block and tackle from the top of the support to the top of the arm.

[ 05-31-2005, 02:57 PM: Message edited by: PatCox ]

whb
05-31-2005, 02:05 PM
Get your attachment low on the bow. The molded in place attachments are often too high and force the bow down. If that is your situation use a bridle and rig it under the tip of the bow.

Otherwise the boat will dig in.

G'luck

Howard

Meerkat
06-01-2005, 01:14 AM
It will be a lot lighter if you fill it with helium... ;)

formerlyknownasprince
06-01-2005, 05:04 AM
The biggest problem with an inflatable is that it is too light.

I had mine tied alongside for the closing night of the Sydney 2000 Olympics. We got hit by a 45 knot gust that literally flung the inflatable (with 3hp outboard) up in to the air. We were lucky that it came back down right side up.

No way would I tow an inflatable in anything but flat calm conditions.

This inflatable fell victim to a mouse plague a year or so later (they ate it full of about 200 holes) - and it was a genuine $1000+ heavy duty 8' marine inflatable - not a cheapy. :D

Ian

Stiletto
06-01-2005, 04:34 PM
I thought Australians kept carpet snakes to deal to the mice. ;)

Andrew Craig-Bennett
06-02-2005, 04:12 AM
It WILL flip over, sooner or later; inflatables ALWAYS will, no matter how they are towed, which is the reason for NEVER leaving the engine, fuel tank, paddles or anything else inside it.

I use Ian McColgin's method - hitched up close to the transom, when towing our little 8ft Avon, but Jeffrey's advice is also sound.

formerlyknownasprince
06-02-2005, 06:04 AM
I thought Australians kept carpet snakes to deal to the mice I've caught the same carpet snake twice in the last 6 months - two doors away each side of me - both times because the neighbours were squeamish about snakes. I took it down the bush and let it go. I think we need a few more around.

Ian

Ian McColgin
06-02-2005, 06:47 AM
We once had two inflatables dangling astern while anchored in a gale - my old Tinker and a visitor from the Island. The boats lept in the air and wound around each other like a mating ritual, suitable inspiration for the owner of the other inflatable and myself.