Dinghy outboard as emergency auxilliary power?

[mpaxman]

A recent thread ('outboard for inflatable dinghy') garnered general agreement on going with a smaller and thus lighter engine for dinghy use. Certainly a small engine tends to have plenty of power for normal dinghy purposes, one doesn't need to be able to plane a dinghy to and from docks or shores. However, a friend of mine asked about the relative value of a dinghy and motor as additional auxilliary power for that time when the main engine quits in a situation where there is no wind or manuevering needed to tight for sail.I would be interested to hear thoughts from the forum on whether a larger outboard might be justified with the back-up power consideration in mind.My buddy and I had a charter boat run out of fuel and then were subsequently becalmed in Rosario Strait (in the San Juans). The current was carrying us toward a tricky passage rather than down the middle of the strait as we desired. While a chase boat was being sent from Anacortes, WA (by the Victoria, BC charter company), we kept the 28' Catalina from being swept into the passage by towing it with the dinghy. Lesson learned: Don't trust the check-out man when he says "The fuel gauge isn't working, don't worry, the fuel tanks are full, I filled them myself" The charter company paid for the chase boat and also knocked a day off our charter price for the inconvenience. It was an adventure

 

[tweitz]

Dinghy as a tug

Even with a big engine, I would be disinclined to use a dinghy as a tug except in relatively wind free weather, but I do recall seeing an article somewhere a couple of years ago (Cruising World?) discussing how to use a dinghy as a tug, inlcuding how to tie it along side, etc. I do think too large an engine is a hazard on many dinghies, especially inflatables.

 

[tom]

size of boat??

It would depend upon the size of your boat and what you plan to do. Any motor will beat a paddle!!!! But if you want to really move a 40' boat with your dingy motor you'd better have a BIG dinghy. we had to have a tow because of our prop shaft. It was a little rough and windy. The towboat had two 200hp outboards and he had some trouble. Nothing major but it wasn't all that easy. Now the same conditions with an inflatable dinghy with a 20hp outboard would have required a lot of skill. With a 5 hp it would have been nearly inpossible. If I was wanting a backup engine using an outboard. I would mount an outboard bracket on the stern of my boat. One of those that can be raised and lowered.

 

[patrick]

Sounds like a good time

to drop the hook.It doesn't take too much to push even a 40 foot boat. You may not set any speed records, but you should be able to get to a safe place.If the wind is blowing, and you are on a sail boat, what would you do????

 

[ED]

CAN BE DONE BUT

I have used a dingy and outboard to move a large boat many times. The other side of the coin is if you want to go far as in miles, its not the way to go. The little motor will just not take the load a big boat offers. yes it will move but he small motors will get hot overheat and burn up. i know of a small mercury on an inflatable that caught fire. It was being run at wide open throttle for a few hours to get up the bay against the current. if your moving from a dock out to a mooring in nice weather not to far then maybe you could use one.

 

[Peter]

That's what I do

I have a Catalina 27 that is outboard powered. The regular motor is a Johnson 2-stroke 15HP. Unlike many of the responses to the other thread, I like a fast dink, so I have a 9-ft inflatable floor dink with a 6HP Johnson OB that planes the dink at 16+ knots with one aboard. Great for exploring in the boonies. The dink folds up to store in the area under the cockpit (where an inboard would be if my 27 as inboard powered), and the 6HP sits on a bracket on the stern rail. The fuel mixture and the fuel fittings on the 6HP and the 15 are the same, so they swap easily. While I haven't used the current 6HP setup as an "auxiliary to the auxiliary", in the past I had a situation where the 27's main engine crapped out on a club cruise about 150 miles from home, in Tomales Bay, CA. One of the other boats on the cruise had a dink with a 9.9HP Evinrude. He rafted up to me for about 1/2 hour while we swapped out the motors, and then his 9.9 got me all the way home very happily. Many 27s use 6HP's as their main motor. The 6HP weighs about 50 lbs, so it is a little bit of a handful to move on and off the stern rail bracket, but is manageable. I used the 6HP and dink to tow a disabled Cat27 into Half Moon Bay several years ago, and found the best way is to attach the dink "at the hip" of the tow, and let the person at the helm of the tow do the steering.I also have a slow soft transom dink with a 2HP Evinrude when I don't need the other dink's speed. I have used the 2HP on a stern bracket on another sailor's 27 (which had an atomic 4) to get into the berth on SF Bay when the A4 quit. The 2 didn't have enough power to provide more than minimal steerageway, however.

 

[Rich]

You're on the outer limit of size

After owning a Catalina 25 that used a Honda 9hp outboard as its auxiliary I thought about that same issue and came to the conclusion that if your boat is light enough to be effectively moved by an engine that would still be light enough itself to be used with the dinghy, then you get a big boost to your safety/redundancy arsenal by going with the largish outboard.In your case, I think the Catalina 28 is about as large a boat as you could effectively move with, say, a 5-7 hp engine that could still be used on a dinghy, so you might want to rig whatever engine mount you were going to have on the transom and try out engines in that range. If it works, I would think it an excellent safety option.

 

[John Nantz]

Small Outboard is Okay

As Patrick said, it doesn't take much to move a large boat. Here's my experience.Our fairly-new-to-me 35-foot boat ran out of fuel in the main channel of Puget Sound between Kingston and Edmonds. This was a nice day with lots of other boats out and about and quite lumpy "seas". The wind wasn't much so we were motoring home. You know the drill - have to go to work the next day.Anyway, I launched the dingy and threw on our 1965 Johnson 3hp longshaft. The 3hp back then was measured at the head - not at the prop like newer outboards. Anchoring was not an option where we were - note chart depths attached are in fathoms, not feet. Also, the shipping lanes are on one side and the ferry traffic was just ahead of us.This was the first time I ever towed our boat and was I surprised - we were doing a tad over 4 knots through the water with this tow rig setup. It works! No problem. And, I don't think I had the feathering prop on at that time, either. Towed the boat over to near the shore where we could drop anchor and then went after fuel at Kingston.Bottom line: you don't need lots of horsepower for this type of situation.As you approach hull speed the power requirements for that extra 0.1 knot REALLY increase - that's why puting a larger engine in or going to a prop with more blades dosen't hardly buy you anything. That's why my brother-in-law needs 500+ horsepower (how much hp are twon Chrysler hemis?) to go three times faster than my 24 horsepower in the same length boat.This is real-world experience. Hope this helps.P.S. There's nothing so bad there isn't some good: I now know where "empty" is on the fuel gauge!

 

[tom]

Yep it doesn't take much in good weather

But even without a dinghy involved moving against the wind requires some horsepower.My brother and I were anchored in a cove on a lake one night . His boat was 28' long and had a 9.9hp outboard. well the wind came up strong in the early morning hours and the boat started sailing back and forth like an angry junkyard dog. we were only 75' from the rocks!!well he decided to start the motor and get to a safer place. well even with the long shaft 9.9hp at full throttle we couldn't move against the wind enough to get off of the anchor. we sailed back and forth until dawn. Shortly after dawn the wind died and we motored back to the dock with the lake looking like glass. As said earlier it all depends upon what you want to do. Almost any motor will move you short distances in calm conditions.

 

[Windwalker]

better luck pushing than pulling

My inboard on my C30 overheated & so I found myself using my dinghy, at first towing, then side tied, and finally stern tied with the bow of the inflatable tied directly to the stern ladder (low on the stern). This setup is by far the best with no weaving bucking or encountering waves (they are broken by the sailboat hull). I found that the power transfer was much more efficient and the inflatable bow acted like a big cushion (heck that's what it is!) on the transom. I only had to put my 15 HP outboard to about 1/4 to 1/3 throttle. We motored like this for hours back to the marina with little extra effort (at about 4 knots), except one person was in the dink (me), & another was steering the sailboat. It was stable enough that I climbed out of the dink onto the boat & grabbed a beer; to soothe my frazzeled nerves