Towing a Dinghy: How much drag?

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SailingontheRiva
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Towing a Dinghy: How much drag?

Post by SailingontheRiva »

I have a 1998 :macx: with a 50 HP honda and want to buy a dinghy for my long trips to tangier island in the Chesapeake bay this summer and need some advice about the buying the correct size tender for the job. I don't have a lot to move around so I was thinking about buying a 9' zodiac, but I don't have any experience towing a dinghy.

Do they create a lot of drag when towing? What would be the difference in drag between a 9' and 10'? I know I can stow it, but it would be our life raft in an emergency.

BTW I was in West Marine the other day and actually asked an employee if he pulls his dinghy while sailing. I immediately realized what I had said and we both got a good laugh out of it. Hahahaha! :P
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Re: Towing a Dinghy: How much drag?

Post by Hardcrab »

Drag is there the faster you go, but no real issue, IMHO.
I do notice needing to add correction the steering when towing using only one of the stern cleats and thereby causing drag to that side.
A nice bridle made up to tow from both stern cleats would best best to keep the drag centered, one would think.
At sailing speeds, it's a total non-issue unless you're racing or something, IMHO.
Make sure to use the poly type floating line for all towing.
The prop will thank you.
Also, make it long - 30' to 50'.
The dingy should ride behind the wake at speed, but remember to snug it in close when you get close to docks and such.
(Been there, done that, big mess)

IMHO, I would use the shortest dingy to get most, if not all, of the job done, and then accept making two trips when needed.
Bigger may not equal better for many practical reasons like extra price, extra weight, extra stowage problems, etc.
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Re: Towing a Dinghy: How much drag?

Post by March »

As pointed out above, it's not an issue for the Mac. It may be an issue for the dinghy though. We broke the dinghy's nose, plastic handle by dragging, even though half of it was out of the water and riding the waves. Make sure you have a bridle around the dinghy and do not tow it only by the nose handle.
What we do when we dock is, we pull the dinghy close to the side opposite to the one we dock, nose out of the water, and cleat it securely. Never had a problem with it.
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Re: Towing a Dinghy: How much drag?

Post by bubba »

We tow our dingy almost always and it slows our boat about 1 kt motering or sailing, we usually don't tow at top speeds ( max about 10 kt) to save wear and stress on the dingy. We have a Mercery 9.5 ft with an inflatiable keel and floor so it tracks straight and the bow stays up on top of waves really well. We use 100 ft of floating line with a 3 point harness with a heavy clip and shakle with a float and tow it about 75 ft behind us so we don't hear the waves splashing on it. When at anchor or at dock we use a long cable locked to the boat to keep it safe. If I had to do it over, I would buy one of the newer catamaran style dingies so only the sides are in the water and have less drag towing and are very stable.
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Re: Towing a Dinghy: How much drag?

Post by DaveB »

I have a Solstice 9.5 ft. from West Marine for $400 and tho they say don't tow it I do and at 38 lbs towing 12-15 ft. behind boat has about a 2-5 lb pressure. It has inflatable Keel and air floor. I use a 2.5 Suxuki 4 cycle outboard (29 lbs).
I never tow with outboard and have fixed bracket on stearn for easy removal.
I have had 4 people on board with weight of 875 lbs and works great but total weight on sticker says 800 lbs.
If wind is to high I store it on bow partial deflated or just roll it up and store it in Vberth.
At 38 lbs it is easy to haul up on deck and built very well.
Dave
SailingontheRiva wrote:I have a 1998 :macx: with a 50 HP honda and want to buy a dinghy for my long trips to tangier island in the Chesapeake bay this summer and need some advice about the buying the correct size tender for the job. I don't have a lot to move around so I was thinking about buying a 9' zodiac, but I don't have any experience towing a dinghy.

Do they create a lot of drag when towing? What would be the difference in drag between a 9' and 10'? I know I can stow it, but it would be our life raft in an emergency.

BTW I was in West Marine the other day and actually asked an employee if he pulls his dinghy while sailing. I immediately realized what I had said and we both got a good laugh out of it. Hahahaha! :P
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Re: Towing a Dinghy: How much drag?

Post by bubba »

One thing to think about, buy one of the little battery pumps along with a foot or hand pump. The battery pump may seam slow but it will pump up your dingy almost 80% and it is a breeze to finish it off after rigging your boat. To store your dingy use the battery pump to suck the air out and it will fold up nicely. Try to buy a dingy with a folding bag with cinch straps, not a bag that you have to try to slide your dingy into they don't work too good.
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Re: Towing a Dinghy: How much drag?

Post by DaveB »

Thats what I do as the coleman pump doesn't get the boat up to max. pressure. I also use the elect. pump to deflate to get all air out for storage.
I have a 15 ft. cigrette plug extension so I can pump it up at forward deck.
Takes me 10 min. to inflate Keel,floor and 2 pontoon chambers with Boston valves.

Dave
bubba wrote:One thing to think about, buy one of the little battery pumps along with a foot or hand pump. The battery pump may seam slow but it will pump up your dingy almost 80% and it is a breeze to finish it off after rigging your boat. To store your dingy use the battery pump to suck the air out and it will fold up nicely. Try to buy a dingy with a folding bag with cinch straps, not a bag that you have to try to slide your dingy into they don't work too good.
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Re: Towing a Dinghy: How much drag?

Post by Terry »

I have a 9'9" Titan and it weighs 78 lbs, (I can't imagine how a 9'5"inflatable weighs 38 lbs) and I have a 60 lbs Honda 5Hp on the transom. When I tow under power it takes an extra 500 rpm to keep pace with another Mac (not towing) doing the same speed as me. I absolutely hate towing a dinghy and only do it when on extended overnight trips because it becomes a nice toy to zip around on when I get bored. My dinghy has an inflatable floor and keel so tracks well but still slows the boat down and causes it to steer to one side when tied to one side.
In hind sight I wish I had done two things differently, one - get a smaller 8'6" model and two - get it made of hypalon instead of PVC. I have only had my Titan for five years and it only gets exposed for a month or so in the summer, yet it has already become sticky and gluey from the suns' UV rays breaking it down. I even used 303 protectant to preseerve it but to no avail. I guess I should have made a cover for it to keep the sun off but I did not expect the short duration of each summer to damage it this soon. If you buy an inflatable, get hypalon and save yourself replacing it in a few years.
Having a dinghy to use at each destination is indispensable, you will enjoy it, but it will slow you down and you do have to be careful when manuevring around marinas.
One more point, you never tow a dinghy by the nose/bow handle, there are two d-rings on each side just aft of the bow that you tie a bridle to and tow from there, the bow handle can have a third safety line loosely attached with slack to keep the tension off in case the main bridle fails.
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Re: Towing a Dinghy: How much drag?

Post by restless »

We tried towing once... An avon redcrest. Floppy floor job. It was awful! don't even consider a free one, it was like a drogue/sea anchor. We ended up getting a toy dingy for £20 as we rarely have far to paddle, and with the electric pump it blows up in no time and even better stows to nothing.
I may consider something a bit more substansial when I've built the arch and davits.
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Re: Towing a Dinghy: How much drag?

Post by Boblee »

We tow a 12' aluminium Dinghy with a 15hp Honda full of fishing gear, fuel and water and really don't have a problem at hull speeds or below 8k's neutral tide and wind but if powering up yes it will basically pull you off plane and you lose minimum 6k's top speed.
We tow the dinghy on the second wave fast or slow, have changed it about but mostly only use one stern cleat we have now towed it for thousands of k's and countless h'rs both sailing and motoring in rough and smooth waters and only one major mishap when I forgot it was there when beaching (at speed) and it cracked the motor cowling.
If I didn't need it for fishing or carrying extra gear we would use an inflateable or preferably dock as I am very nervous with the lizards here and a small inflateable seems to be flimsy.
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Re: Towing a Dinghy: How much drag?

Post by Trouts Dream »

Being mostly land locked in Alberta we went with a Sea Eagle inflatable kayak for our tender. I mostly just the two of us and we can both paddle. Although i wouldn't want to do major previsioning with it (thats what courtesy docks are for) we actually use it for an evening paddle most nights.
Tows well under sail but I bring it right up so the bow is tied to a rear stanchion when under heavy throttle.

Inflates with one of those large barrel double action hand pumps (like the old bicycle pumps) in 5 minutes.

If I spent more time in tidal waters I may want a proper tender but for the occasional use this has been awesome. Kind of like keeping with the versatility of the Mac.
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Re: Towing a Dinghy: How much drag?

Post by Sumner »

We don't have an X or M, but do tow our dinghy full time behind our S. We started with it on a line off the stern, but didn't like that as there were still situations where we got the line around the rudder and/or the outboard.

I used the swim ladder as a tow bar and most of the time have the bridal on the dingy pulled right up to the ladder...

Image

We have been really happy with this arrangement and if desired it can be let out to any distance desired behind the boat, but we tow all the time with it close behind the boat .......

Image

....as in the picture above.

Here is a link to how I built it...

http://purplesagetradingpost.com/sumner ... de-17.html

Not too much to it, just the connector on the bottom and the bar to hold the ladder out horizontal. The other nice thing with the ladder out horizontal is it is very convenient to stand on it getting into and out of the dinghy.

Most of the time we have the dingy outboard on back rail of the Mac....

http://purplesagetradingpost.com/sumner ... de-12.html

With no outboard on the dinghy it tows flat. With the outboard and gas on its stern it tows with the bow higher than I like. I'm going to make a new tow bridal like this...

Image

....and see if that helps to keep the bow down and also hopes it takes some strain off of the tow attach points on the dinghy as we will be pulling mainly from the stern if the bridal works. In Florida we will probably have the outboard on a lot more, so this could possibly be an improvement if it works. I'd also think if you could tow it with the strain on the transom of the dinghy that might be more important with the higher towing speeds that are possible with the X and M.

c ya,

Sum

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Re: Towing a Dinghy: How much drag?

Post by Kelly Hanson East »

I pull a Watertender 9 foot hard plastic dinghy behind Catigale - I havent noticed any difference in either fuel consumption on a 15 mile cruise or, if I let the tow rope go, in speed of the boat with the motor at 3000rpm. I estimate that any drag losses of speed/fuel economy are thus less than 5% (the smallest change I can detect in either measurement). At 3000 rpm engine speed (7smph) the tow line has something like 50 pounds force on it - estimated by my pulling on it.
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Re: Towing a Dinghy: How much drag?

Post by KayakDan »

We pull a Brig Baltic,10'4",96 lbs,with a Honda 2hp,without any problems. We use a Shockle as a snubber to reduce the stress on the towing line,and run a bridle to both tow rings.
I think it slows us by about 1kt when sailing.

Ever tried riding in your dinghy when your boat is under sail? It's really a new perspective!
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Re: Towing a Dinghy: How much drag?

Post by c130king »

KayakDan wrote:...Ever tried riding in your dinghy when your boat is under sail? It's really a new perspective!
Set the autopilot while under sail, climb into the dinghy, ease yourself back a few boat lengths, and then video the boat sailing by itself...that would be cool! 8)
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