Towing a dinghy at high speeds

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I'm wanting a Walker Bay 8 RID or a Portland Pudgy dinghy for use with my 22 Cruiser. They are too big and heavy for the cabin top and I don't want to tow on a line at reduced speeds so I have another idea. I want to build a tow hitch similar to a car's trailer hitch and tow the dinghy attached directly to the stern of my 22.

This tow hitch would be made of stainless steel tubing and attach to the transom. It would stick out slightly beyond the outboard(s) and the dingy would attach to it "trailer style". The mount would straddle the outboard(s) and would probably have three to four mounting brackets, points of contact with the 22. It would be removable for towing the 22 behind my truck.

The bow of the dinghy would be out of the water and it would ride on its transom in the power boat's wake. I think this would allow it to skim/plane along behind the towing boat at what ever speed it is traveling at. The idea is to keep the weight of the dinghy off the C-Dory, keep the dinghy in/on the water eliminating the need to lift it, and to be able to cruise at top speed when I want or need to. I could also use the dinghy as a trailer and carry gear in it like extra fuel. If I've explained this well enough for you to understand the concept do you see any problems with this idea? Do you think it would work?
 
You might want to check it out on flat water with wakes and stuff before you go out in the ocean. When towing in the ocean I prefer to have both vessels be in sinc with the swell and set the tow rope at a length that will keep us in harmony instead of fighting the swells. Line is working while towing where a tow bar would not have any give.

With your dink so close it will be in your wake, possibly getting real lift from the wake but I think the challenging part will be swell that is steep and short.

If you do this, I would suggest a quick disconnect. Usually with a tow rope a sharp knife is close by.

I see the big boats mounting them on board. I see the little boats with tow ropes or light dinks on top.

Never tried it so I don't know from how it will work, but you don't see this on the specialized tow vessels. Good luck.
 
We have done this with a variety of dingy's and closer does tend to be better.

A couple of things, the spray can fill up the dingy, you may need a cover. Definitely take any engine off of the dingy.

Two ropes from each side of the stern of the dingy to the Cdory would be helpful, not too tight enough for the boat to move side to side but not get into too much trouble.

There was an outfit in Utah that make a hitch like you are describing but it was mounted off of the swim deck, that is generally how we towed ours.
 
I don't see the problem of towing a dingy on a line. if set up right and well behind the boat you should be able to tow a dingy at cruising speed, 20 knots, in mild seas. Anything bigger then a 3 ft well and you are not going that fast anyhow. I see lots of boats towing their dingy and we towed ours in maryland behind my fathers Chris craft. In a 22 cd you would have to tow right behind the engine with your set up and that is right in the wake. when you slow down you will have problems with the closing wake lifting the back of the dingy and shoving it into you. Let us know how it works and take Pictures but sounds like reinventing the wheel when the wheel already works.
 
So here's my dilemma. I've been told not to tow a dinghy faster than about 8 knots, sailboat and displacement hull speed. Now maybe that is just sailors talking or maybe that is a recommendation for an inflatable, which I also own. I wasn't aware that it might be ok (not to mention safe) to tow a ridged dinghy at planning speeds. I think I’d worry about it back there.

My thinking is that although you can tow a trailer or another vehicle behind a car with a rope (I've done this on the rare occasion) it doesn't work that well even for short distances. So, why not tow a dinghy directly behind the boat with a hard connection? If the dinghy is attached to the boat with a hard connection that swivels in all directions it would move right with the boat. The dinghy should ride on top of the wake being pushed out of the water. Neither would it be able to hit the boat when slowing down.

As far as deep short troughs go I'm guessing it would ride like a cork and as long as the hitch connection has all the flexibility in the world (say a pintle style connection) it should be fine. That's one reason I suggest the bow being out of the water. That and to make the dinghy plane on its stern hull section. Of course this will take some testing and maybe some trial and error. Remember that no one had flown an airplane until it was invented. One day people might wonder why this hadn't been thought of before.

Let's see, I'll need a ridged dinghy for testing, some PVC pipe to build a prototype of the mount, some ss tubing, a TIG welder... I'll have to get back to you on this one.
 
The Walker Bay 9' with inflatable sides, only weighs 89 lbs. This could be managed by a rack over the pilothouse or cockpit. We have brought dinghies up to 350 lbs using rollers and a winch (larger boat). You could make rollers and a way to bring the dinghy up onto a rack.

You might also consider towing the dinghy, with the stern on the boat, and the bow in the water--not sure that there is much advantage, but people tow inflatables this way at low speeds.

We have towed a 12 foot Al dinghy at speeds up to 40 mph---on a tow line, it dances all over the water. There is a fair amount of drag--more than if you bring the dinghy aboard.

As noted, I would be most concerned with following seas. Getting water in the boat is a real fear, and a cover might even make the situation worse, because it has to be secured below the gunnel and may actually scoop up water. The PVC will not be strong enough to survive the full speed trials. It also clutters up the back and is another item to store.

In the PNW, I can see the advantage of an RIB or hard dinghy because of the rocks and barnicles, etc. Even with our RIB (heavy) we anchored it off the shore, with long lines to bring it to the beach, as the tide went in and out. This avoided using the wheels, or having to drag it up a rocky beach or over trees etc.
 
I have also been thinking about this issue of towing v/s lifting.
Though your idea sounds secure, I would not choose this option since the c-dory tends to put out a large following wave and would do so at the moment after you come off plane. The effect would be to lower your hitch point just before the wave hits it. This could swamp the inflatable and put a great deal of upward pressure on your A-frame hitch thing.
So, you could design your hitch mount with 4 mounting legs with deep screws, pull the kicker, cover the boat and always have to decelerate slowly, but by that point you will be asking yourself "why not just use the rope method or pull that thing out once and a while?

I may at some point end up with a RID inflatable myself and the real issue is not getting it up on the roof when the boat is on land or at the dock. Getting it off of the roof is also not an issue. The issue is getting it back up on the roof while on the water without a dock to work from and being too far away from a dock to tow it over for loading.
How many times will you be in this position? Answer for me was never, so the rigid hull remains an option.
 
Capital sea, I have to be missing something. Every time we use our dingy, we are away from a dock and anchored--thus it has to be lifted back on the roof from the water. I have never put a dinghy on the C Dory from a dock--although it might be easier.

As the weight gets more, lifting a dinghy aboard is much more diffcult. We still have not yet made the SS mount for the Garheaur davit on the side of the boat, but with that, a 90 lb boat could easily be lifted to the cabin top.

Here is the cardboard mock up. We routinely lift over 100 lbs with the davit.

Gaurheur_davit_instal_004.sized.jpg
 
My concern would not be the initial pull from the dingy against the stern but rather the repeated "hammering" that the stern would receive from the dingy. By this I mean that the tension on your stern, rode and dingy would be constantly changing from no tension to a great deal due to the dingy bouncing back and forth, taking up slack and then releasing it. Somewhat similar to an air hammer, chisel drill etc. Think of how they remove the nuts while changing the rims on your car, it is that repeated hammering that breaks loose the tension.

I know that the easiest way to destroy a trailer or frame mounted tow hitch is to slam forward instead of ease forward and bumpy roads can cause similar issues. I think you would have to find a way to overcome this via rubber or a shock arresting device.

One of the great advantages of my "office" overlooking the water is to watch how the barges are handled by the tugs. They go to great lengths to avoid sudden forward movement or shocks on the huge cables.
 
Thataway, perhaps you were missing my point.
The kind of boat selected depends on how and where you will be using it and the need to get the dinghy back on the roof from the water depends on where you generally are when it is put into use.

Round here, towing a dinghy behind is not such a big deal as much of the Puget Sound is protected from big swells. If I was going to run up to the San Juan Islands or up into Canadian waters I would make the run with the dinghy up on the roof where it would be loaded from the parking lot or dock. After crossing open water and deploying the dinghy, a dock would never be that far away and I would reload it on the roof prior to the long run home, so for me the weight and loading/towing issue would not be a problem. As a result, the design, stress issues and added risk of the rigid tow mount would not be worth the effort and the compromise detailed above for having a rigid dinghy would be the way to go.

Down in the Florida area, the close by dock element may not exist and I might be less inclined to buy a dinghy that I could not pull out from the water.
 
We looked at the Walker Bay 8 and thought it too heavy at 71lbs with only a max load of 425lbs. We went with the Alaska Series 240 TDS because it only weights 45lbs and has a max load of 837lbs. I have no problem single handling it on and off the roof of our 22. This inflatable rows great and does well with the little 27lb Honda air cooled outboard.
The TDS tenders also have a 3 point tow harness, but have no experience towing one.
I suppose if you wont to sail the Walker Bay has that advantage.
 
Capital Sea--actually my comments were made in reference to the PNW--where, for example in the Broughtons, Desolation sound area, etc--when you anchor, there is rarely a dock available. Your suggestion of towing I guess makes some sense, if that is what you want to do with a dinghy. I'll admit that I have spent little time in Puget Sound--I start at Sequim and run on up--and there there is often rough water (at least the times I have done the trips).

I only towed my 12.5 Avon Rib only once in the 3 years we were cruising for 6 months out of the year in that area in our Cal 46. That one time was when the wind came up to a point where the anchorage (ball bearing type rocks) was unteniable, and we elected to tow the RIB (much more seaworthy a vessel than the average dinghy used by C Dory members) about 10 miles to a protected anchorage, and we almost swamped the RIB due to rough seas. Even a 500 gallon per hour bilge pump had difficulty keeping up with the water coming aboard at 7 knots.

There are a few times when there is a dock where we will put the dinghy in the water. An example might be one of the float camps, without connection to land, and we might want to go hiking, so we will launch the dinghy to get to land. But in that case, we launch the dinghy over the seaward side of the boat, not onto the dock. Just different way we use the dinghy. With dogs, the dinghy is an essential.
 
Just a personal preference, but I would never try to tow a dinghy at speeds much greater than displacement speed. I once towed my Avon inflatable from Port Renfrew to Victoria, and again around the tip of Vashon heading for Quartermaster Harbor (never learn) and both times I managed to swamp it when the boat speeds peaked beyond theoretical hull speed in steep seas. This was in a sailboat. If just once you swamp an inflatable while towing it when conditions get bad you will find out what a handful they are. And then there was the adventure gained when I was towiing near whaletown up in BC. Wind got under the dinghy and lifted it up off the water about 10 feet and it spun like a kite, with the 2hp honda on the transom. Bad part was when it landed in the water upside down.
 
Anyone dumb enough to do it twice deserves what he gets. But I have finally learned. I can actually see something going wrong and endangering a c-dory. A dinghy full of water in bad conditions could possibly drag you backwards, or the painter could get fouled in the prop. I had some friends that actually towed a 13' zodiac with a 30hp suzuki up the oregon/washington coast to the san juans behind a 29' cascade sailboat. They said one night it tried to climb up the stern into the cockpit. Now that would be a scary experience. I finally learned to deflate and stow, no matter how much trouble it was.
 
While we are on the subject, it is not advisable to tow by the bow eye with an inflatable. We put thru bolted eye bolts through the transom, and attatched lines to this to take the towing force. The tow rope was kept in the center by a line to the bow eye--but towing by the bow eye, can cause the fabric or glue to fail.
 
Pro Hobiest,

I looked at and seriously considered a Portland Pudgy for a dingy, but on the 22 Cruiser I was not willing to travel with that 104 pounds up top. Did consider towing it but did not like the idea very much, although the Pudgy is IMHO the best small boat dingy/tender out there. We have friends with a non C-Dory (B-boat) that tow a Walker 8, pulled up tight onto the swim step, just slightly off center, where it rides tipped a bit very steady and stable. We cruise with them at about 18 - 20 knots and it sits right there, taking very little water, even in big waves. Last summer we negotiated Georgia Strait in 6 foot following seas and it did fine. However, when se got up to Princes Louisa, the 2 of us in that Walker only had about 2 inches of freeboard on it's transom. So, I have an Alaska Series, donut boat (240TDS), and we put it (45#) on top. We are currently considering some type of arch over the OB's and splashwell and having the inflatable bridge from there to the aft cabin wall.

Harvey
SleepyC :moon
 
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