RE POWERING THE BOAT

[alex]

Hi Folks!!!!

after a short research on this website I don't found the answers I am looking for...

I have 2 x 9,9 HP Yamaha's in our Tiki 38 which I consider are awesome motors. I spend less than 3 liters/mile when just motoring  , at a speed of 4,5 kn with one motor or 6 to 7 with both. and much less when motor sailing..

the purchase cost I researched recently was $ 3090 us dollars each, including the newly hydraulic tilting .possibility (so the reseller)

In my cruising style, the downsides of those motors are mainly the combustible they use: gasoline. there are 2 or 3 main problems with  it: quality, price and gasoline motors are much harder to maintain than diesels.

I am seriously considering re power the boat as part of a general refitting, and i am thinking either in buying new ones (mine are made in 1998, so almost 15 years now) or change for one 2 two Nanni inboard diesels, (if one 25 HP, if 2 .. 2x 14 hp or even  2 x 10 hp which run with lower RPM).

I think Nanni diesels are reliable and less noisier and also have a great mileage burning diesel. downside: the cost of upgrading and maybe noisier than the Yamaha's

In my cruising life i spend 90% or more of the time at the anchor and rarely I get into a dock, even for refueling. most of times refueling is made with the dinghy... so one single motor placed in the center, would work as well. I will miss the fine maneuvering that I have in present times though.

I would love to start a serious discussion about the pros and cons about the different options and horse power... I have even considered the diesel electric option, but I think its not for me and not for my budget. after a brief research I think the technology is still too under developed and not energy efficient for the kind of boating I do, which involves many hours of motor sailing sometimes.

I am not happy in having large amounts of gasoline on board as we had on the passage from Tobago to Brazil (gasoline in Tobago cost around 47 US cents a liter, so we got over 600 liters, which resulted in a very good deal as we found out later)

As Luis posted earlier in another discussion, my motors were shacked and really wet from all sides, with all the pressure water coming from the heavy seas. Salt was a real pain not only for the crew, but for the motors. An inboard would be less exposed and with diesels , you don't have the carburetor problems we had to suffer.

there is another consideration to do before taking a decision..its about the maintenance and the cruising noise when motoring. the yamahas are pretty quiet when the seas are fine, but turn really noisy when there is some choppy seas and all the vibration starts... i have mine mounted on silent blocks, but this seems not help too much to stop all the noise.

As you can see now, I have a love-hate relationship with the Yamahas... the worst of it is that I am not happy carrying gasoline on board and all the preventive maintenance they need . will be a Nanni diesel solve all or part of that?

a further question that i am thinking about is that at present the propellers are situated at the very gravity center of the boat. with an inboard diesel (one or two) having a long shaft the propeller/s will act more aft, and i have no idea what the results will be, specially in heavy weather situations where cavitation is more likely to appear...  I don't have that problem in present.

Please when giving advise, take in account our cruising stile. I am not a Purist, and we are not too much into inland motoring ( we plan to cruise some rivers in future though), we are sometimes passage sailors/cruisers, and more often island hoppers... we are on a budget and we like to take advantage from cheap (????) combustible prices. we are also not into excessive carbon footprint, but also not into extreme savings.. we just try to keep a balance. we also have large solar panels and a big wind generator that fill 100% of our energy needs , fridge and freezer included. we just run the 2000 i Honda generator to run power tools, milkshakes and equalize our battery bank (4 x 230 VA/ 6 volt, deep circle golf cart ) once a month or so.

waiting for your input guys....

cheers

[John Allan]

Hello,

I am renovating my Narai MK IV, which  has a horrible 30hp Johnson, wanting to repower with the 50hp high thrust Yamaha, I found this when researching gas vs. diesel....http://www.yachtsurvey.com/GasDiesel.htm brings up some very interesting points I had not thought of. Hope it helps!

Good luck

[andy solywoda]

I have had a single 50 HP high thrust Yamaha pushing an enlarged Narai MKIV (Ariki size) since it was launched 9-9-2001.

Twin engines of smaller size enable much better maneuverability as well as redundancy if one should fail.

The Yamaha burns about 5 quarts per hour at about 6-7 knots.  In lumpy seas it is hard to avoid "cavitation".  The main tank is 65 gallons which would give a 300 mile or so range.  Running on the engine would be typically used entering or leaving port, traveling in the Intercoastal Waterway, or maybe moving out of the way of a thunderstorm when becalmed.

There is a lot of information about various propulsion schemes in the archived sailorman/sea people magazines. 

One aspect of using an outboard motor is, if it fails, it can be easily removed and taken to a shop for repair.

I added control lines to the engine to turn it with the tillers and it turned out not to add the advantage I expected, so I removed them. 

I guess all installations have their advantages and their shortcomings. 

 

[alex]

great article.... very interesting.. there is a further article in the same website :

http://www.docksidereports.com/sail_boat_auxiliaries.htm

[John Allan]

Thanks Andy tha'ts very useful info... what is the shaft length on your 50?

I also experienced cavitation with the Johnson which has a 25" shaft. Do you feel a 30 inch shaft would help? I was told you could use two 5 inch extensions to get a 30 inch shaft on the Yamaha? Have not confirmed this as yet.

What is your waterline length, and what is your top speed?

With the current length of my sled the prop will be aprox a foot past beam # 3, I am extending the beam overall to 23Ft and am hopping this gives better waterflow pattern between the hulls,ie. moving the bow wake farther aft... possibly?

[andy solywoda]

I've never measured it.  It's mounted on a sled.  When the boat starts pitching, like when trying to motor into the wind, it is hard to keep the motor in the water all of the time.  My prop is between beams #3 and #4.  It seems to work well enough in the smoother waters of the inlet, then problems in a seaway. 

Waterline is around 36 to 38 ft, seems to hit hull speed at about 8 1/2 knots.  Engine tops out about 10 !/.2 knots. 

Beam is 22 feet. 

The main problem is trying to use the engine to go to windward when there is enough wind to make a sea.  A good sailor should plan the voyage accordingly, or at least work the boat to windward.  Some skippers go out for a sail and go downwind, then turn on the engine when they have to sail back.

[John Allan]

Thanks Andy,

Factory shaft length is 20 inches, so i must purchase after market extensions. Was told you can use 2 which I am still trying to verify? Should see a significant reduction in cavitation with the extended shaft.

Local Yamaha dealer quoted  $368.00 difference for the 60hp (my preference) . With my 35ft waterline I am expecting to make the 10 knots you spoke of with hopefully about 1.2 to 1.5 gallons per hour, of course dependant on circumstances.

Due to work obligations conflicting with my addiction (sailing the Exumas) I need to turn Windchime into a motorsailor when circumstances require. Which seems the proper choice as opposed to not sailing.

Thanks again for your feedback! 

 

[alex]

anyone here has diesel experience?

[John Allan]

My experiences with owning two liveaboard monohulls and living full time in USVI on these boats both with inboard diesels. All I can say is for me with the trade offs/compromises being weighed out..... I am going with the outboard and hopefully my choice fits my needs ?

If I find more useful articles I will pass along to you !

Pura vida

[Jeff Kittle]

We have a Yanmar Diesel 27hp outboard on the port side of our Tiki 46, and a Honda 15hp extra long shaft on the starboard. Both have 4 bladed props. We rarely run both engines at once, There is negligible increase in speed with two so the only benefit is in manoeuvrability. At 5 knots the diesel consumes 1/2 gal/hour while the Honda uses .75 to 1 gal/hour . Both will push us at around 5 knots so the increase in horse power of the diesel doesn't really translate into an increase in speed. We could probably push either one more but choose to go easy on them. Both will cavitate in big seas. (In spite of putting on these fins that are designed to prevent cavitation).  The diesel is definitely louder than the Honda but it usually is called upon when we need to motor because of the lower fuel consumption. Downside of this system is that we have to carry two types of fuel.The diesel is easy to fix - many parts are the same as an inboards', but the Honda is a reliable motor and has never had a problem. Purchase price of the diesel was $1700 (used), and of the Honda was $400 (used). 

Sue

[Demi & Dirk]

@ Jeff:
We started to build a Tiki 46 and have to decide which motors are the best solution for us. On your sailblog (Kittywake) we found, that you installed Epods. Do you use the Yanmar and the Honda additionally to your Epods? What was your experiance with the Epods?
All the best
Demi & Dirk

[Jeff Kittle]

DONT DO EPODS!!! The man in charge of the business may be very nice but he is totally unresponsive to phone calls, emails, and according to some blogs I've looked at he has taken money without providing product. When we built the boat, we had the Epods in the hulls and a single Johnson 50hp two stroke motor that we took off an old power boat on a sled in the middle of the cockpit floor.. Coming down the rivers from Michigan we hit something and broke the fairing around one of the electric motors. The performance just wasn't enough to power us, and the noise of the power "regeneration" was irritating.  Coupled with the worry of taking on water in one of the hulls we decided they just weren't worth it. We had her hauled out and removed the motors and are so much happier. Finally, the Johnson died and we switched to the dual motors for better manoeuvrability.  I personally think the 9.9s Wharram recommends just won't be enough for a boat like the 46 and would go with at least a 15hp.  We motor when we realize we won't make it to a safe harbor before dark, or the weather is threatening to change for the worse and so more power in my opinion is better. I would love dual 50hp! Of course, the weight would be too much so go with the biggest you can get. The extra long shaft is really nice also since the engine box doesn't have to go down as far and there is less chance of waves causing the box to "bang".

Best wishes with the build!!!

Sue

[alex]

The european made Tiki 46 APATIKI has diesel electric epods from MASTERVOLT (well actually Mastervolt bought the former dutch or Belgium company) and they added a Lombardini genset with a large battery bank . that was 3 or 4 years ago and I just emailed them for an upgrade (i wanted and update, not an upgrade, but my poor English still makes me some tricks)  of the experience and they answered as follows:

"There is nothing to upgrade about the electric motors of APATIKi as everything is still running fine !

The last two months we sailed or motor-sailed 1,200 nautical miles from Turkey to Sardinia and we continue West.

If you intend to go electric the basic rule to observe is 2.5 KW motor for each ton of boat.
APATIKI is around 8 tons x 2.5 = 20 KW (we use two 10 KW pods)."

The system is not cheap nor light weight compared with 2 x 9,9 hp Yamaha's ... but I like the idea about having just one Genset  on board placed in the most convenient and alot less noisier, maybe even 100% quiet during short motoring...

alex