Auxiliary motor?

[Air-cooled]

I'm in the process of having a Cutwater 24 built. It will have the Yamaha 300 hp outboard motor. What is the consensus on whether an auxiliary motor should be purchased. It is a $5,000+ option, so it is a little spendy. I may use the boat on the ocean as much as once a year, but probably not more, and likely much less.

 

[NorthernFocus]

...What is the consensus on whether an auxiliary motor should be purchased....

I think you'll find there is no concensus. Might as well start a discussion on Ford vs Chevy. Best you'll likely get from others is a list of pros/cons. A lot depends on where/how you boat. If you plan on troll fishing a good bit it's not a bad idea to put hours on the kicker rather than primary engine. I think you'll find very few Rangers/Cutwaters with inboards that put kickers on them. What's the difference?

 

[Scuffy]

Modern outboards are pretty reliable. Ethanol based fuels account for most of the issues. I don't think it's a problem for an engine in regular use but engines that sit with untreated fuel can suffer from gumming up float tanks etc. Aux motors will suffer the same fate if they run untreated ethanol laced fuel if all the fuel is not used up on a regular basis. On our previous boat powered by an outboard we always treated ethanol based fuel with Marine Stabil and Yamaha ring free. Never had any ethanol based issues. I would use a separate fuel supply for the kicker so if the main fuel ever becomes a problem the aux fuel comes different source. I still treat all gas that I use for the lawn mower, weed whacker, snow blower, leaf blowers, gas generators, rototiller with Marine Stabil. In the past I had some issues but not since using the Marine Stabil. Like what's already been said if your not trolling a lot it's probably not a necessity to have an aux. But if you have a dinghy the dinghy's engine could do double duty as an aux for the big boat if a motor mount was available. Just my opinion here.

 

[NorthernFocus]

... But if you have a dinghy the dinghy's engine could do double duty as an aux for the big boat if a motor mount was available...

Been there, done that. It seemed good in theory. And for an absolute emergency backup for the big boat, sure. But the outboard you'd pick for dingy versus kicker for a large boat are substantially different. Plus if the outboard is large enough to be on any real use as a kicker, then it's large enough to be a real bugger to shift from one to the other.

For the reasons stated in the prior post and more, if you do have an auxiliary engine, it is highly recommended that you put some hours on it on a regular basis.

 

[Air-cooled]

Thanks for these great replies, they have helped me decide not to get the auxiliary motor. Even my dealer (Long Beach Yachts) has now told me that it is not something they would recommend. These reasons not to get it simply outweigh those of having one:

- Expense (5K)
- The main (new) outboard is a reliable motor
- Rare use of the aux motor can make it unreliable
- Additional weight on transom (dealer noted this)

 

[harry ames]

I think your dealer is taking too narrow of a view. The facts are that engines do fail and fail a lot as I read the many posts on the tugnuts site. They fail for all kinds of reasons and usually at the worst time, wind and waves and rocks.

I think the kind of boating you intend to do is key in the decision. If you are doing the Alaska passage, I'd really want an auxiliary. 5 grand for peace of mind is pretty cheap, and yes, the kicker should be used regularly and should be well maintained.

If you are only day cruising and have emergency tow insurance and people close by who can get to you, then the kicker value is less.

High value yachts have what is called a "wing engine" which can be tied into the prop drive train when the main goes down. That is because even on million dollar yachts, engines can go down. Often, it is the insurance company that wants that wing engine.

Yes, the power head may not quit, but what about that sub surface log, or that unintended grounding etc. That is when the auxiliary comes into it's own. Anything from bad fuel at the top of the engine to a problem with the transmission or the prop at the bottom of the engine can make you wish you had the auxiliary. Yes, you can change a bad prop on the main, but try doing it in 20 knots and high waves.

Just my two bits, having flown a million miles on airliners all of which had at least two engines, one of which failed on a flight over the ocean.

 

[LAKERtoo]

.. strange that theres a question that the transom that holds a 300 HP main motor, can't hold an additional 100-120 LB auxiliary ??? Rob

 

[Red Raven]

The transom/swim grid can hold the motor. That is not the issue. I think the comment regards overall weight and balance of the boat. A kicker on the stern adds weight to the stern on one side which you will have to compensate with trim tabs (high speed solution only) and/or distribution of load. We have a dinghy motor mounted on the port stern of our R27 which causes a slight list to port stern unloaded. A store of preferred beverages in the starboard v-berth locker and a full fridge compensates nicely! 😀

 

[MACHZERO]

We boat in the Northwest, and have just traded-in our Cutwater 28 for a Cutwater 30CB. When we acquired the C28, I was concerned about the lack of a "get home" engine...it would have been a first after previously owning a wide variety of boats. Despite "Modern Technology", I've had several experiences where the "get home" engine provided the only way home. Consequently, I decided to "upsize" the motor required for our dinghy and install a secondary motor mount on the swim step. This complicated the task of transitioning ANY motor from the railing storage mount to the dinghy transom, a problem we solved with a removable, manual "motor lift". The six HP Tohatsu outboard weighs 60 lbs and the motor lift makes the transition to either the secondary transom or dinghy's transom a non-event. After installing a "power prop", the outboard would drive our C28 at approximately four knots (full fuel and water). Not enough to water ski, but sufficient to proceed in the desired direction. I've moved the whole installation over to our C30CB, but have yet to test it. If there's an interest, I would be happy to report the results and provide pictures.

 

[Red Raven]

Machzero,

I have a couple questions regarding your auxiliary.

1) what do you mean by "power prop"? Do you mean a prop with less pitch or diameter? (which would increase its RPMs)

2) when the auxilliary is in use do you steer with the aux or fix it going straight and steer with the boats rudder. If the latter, how well does it work?

 

[William Thomas]

I am having a CW 28 , 2017 built and plan on installing my almost new 9.9 Honda 25 inch shaft kicker on the new CW. I have been boating for 50 plus years and would not be without a backup engine. I will be cruising the Great lakes in retirement and things happen!

BT

 

[MACHZERO]

Red Raven:

The Tohatsu came with a prop intended for planing dinghy use, consequently behind the big boat, the motor had trouble reaching RPM. The power prop is designed for use as auxiliary engines for sailboats...it has less pitch and more surface area...works well.

I chose to mount the secondary transom mount on the port side, halfway between the trim tab and the running gear, thinking it would see cleaner water. As it turns out, the motor tiller fits against the swim step railing, which with the assistance of the friction adjustment, keeps the motor pointed straight back.

Steering is accomplished from the helm, although without the flow normally provided by the prop, it's sluggish, but sufficient to maintain a course. If more aggressive heading control is required, a short tap on the bow thruster would do the trick.

 

[Red Raven]

Machzero:

Sounds good. I have similar arrangement but have not had the need to use it (cross my fingers as it is really only for emergency propulsion to get to a safe harbor).

My dinghy motor has the same problem with RPMs and I have ordered a prop with 1" less pitch but haven't received it yet. Hoping that will work. Haven't heard the term "power prop" is all. What are the specs for your power prop?

I was also concerned that I would not get enough speed to steer the boat from the helm with the low flow across the rudder. Using the bow thruster is a great idea (if used with caution dipped to chop etc. to make sure it doesn't catch air).

Thanks!

 

[LAKERtoo]

.. if worried about fuel residue sitting in an infrequently used outboard, disconnect the fuel fitting at the motor after each run when you shut it down and let it run dry .. I did this with my 40hp Merc if it was going to be sitting even 2-3 days and will do it with the 9.9 .. I've never had start-up issues or rough running .. Rob

 

[MACHZERO]

Lakertoo:
One advantage of the six HP Tohatsu is it has both an internal fuel tank AND a connection for an external fuel line. It also has a fuel shut-off that permits running the carburetor dry. The internal tank allows for use of the boat's 2.5 gal designed gas tank storage and eliminates the requirement to carry a separate aux tank in either the boat or the dinghy.
Our marina currently offers ethanol-free gasoline which helps, but doesn't completely eliminate the storage concerns.
Your 9.9 motor will work fine for you...in my case, the motor had to provide for both the emergency "get home" function and the everyday dinghy power. The 9.9 is too big for our dinghy.

 

[William Thomas]

The 9.9 Honda that I will be using on the New CW 28 was used on my 2655 Bayliner Ceria,(9 1/2 ft. Beam). The Honda has a 4 bladed prop that grabs the water pretty well. 25" shaft got the prop deep in the water so no cavitation. I kept the Bravo three stern drive in the water and steered with that. Slow to turn, but worked OK. Ran the motor dry of gas after each use and seemed fine when starting a few months latter. Usually starting with one pull on the rope! Will not use it on my dinghy as too heavy to move around and 25" shaft would not work well. Will be carrying a 6 HP. mercury,(55lbs) for use on the dinghy. Extra weight and space I know but worth it as it actually planes the dinghy with just my wife and I in it! Gets us around pretty quick when the big boat is at anchor.

BT