Suncat as a Power Displacement Cruiser?

[cruz-in]

I concur about over generalizing the results of the article. I look at it as: If one had a very similar boat to the test boat, the out of the bbox engines would perform as described.

The refinement criteria ia the one I am interested in. Here is the way they define it:

Refinement
We measured each engine's noise output at idle, 3 knots and flat out but also assessed them subjectively according to how smooth they sounded and felt, especially when revved hard.

In chosing my "displacement cruiser" outboard, understanding the test was on a different boat, I would lean toward the ones that got the highest score here. The Suzuki and the Yamaha.

[rogerschwake]

  I'm not real sure what your trying to do. Here is a web sight where they are putting pilot houses on small sailboats and they look good to my eye. The sight is www.sailboatrichlands.com and look under current projects. This would be a lot of work but the end results looks great. Hope this gives you some ideas for what you are looking for, good luck.

ROGER

Can't believe you could sell your Sun Cat at that price.

[Shawn]

As far as the refinement impressions the idle one make sense and maybe at 3 knots. But flat out the wrong prop will change the subjective and objective impressions of the engine. An engine that is lugging WOT with the wrong prop is going to sound and feel different than the same engine with a proper prop.  I couldn't find the Yamaha's props pitch but the Suzuki is pitched lower than the Honda. It will have an easier time getting to full RPM. If the Honda is failing to get to full RPM it will be harsher feeling (lugging) and possibly louder compared to the Suzuki and that is the impressions in the test. A change in prop pitch for the Honda may change that. That is why it would have been great if they had recorded RPM to show how that differed between the engines at WOT and maybe to compare noise/harshness at the same RPM. That thread I linked to has examples of this with the Tohatsu 6hp and different props.

Having said all that that I own two Suzuki outboards (2.5 and 9.9B) and am impressed with how quiet they are. My 9.9B shocks me every time I throttle back to idle, I think it stalls it is so quiet. I'll make a video of that next time I am on my boat. They are different engines than the 4/6hp Suzuki though.

For displacement cruiser noise is certainly something to consider. Availability of a high thrust prop would be worth thinking about, shaft length, ability to charge batteries from it and ease of access to the controls on the engine would be useful too. I had the original version of the Sailpro and can speak from experience that shifter location makes a big difference... esp. when docking. It was difficult getting through the rear pulpit to reach to side mounted shifter. When docking I didn't use the shifter as I didn't want to stop watching my progress for the amount of time it took for me to climb backwards to get into reverse. Once I had shifted into neutral for my final turn I was just working with inertia and a spring line to get the boat in place. The later models with the shifter up front would have been much easier to use and remote controls would have been simpler yet again.

Shawn

[Catawampus]

I'm very happy with the Yamaha 4hp 4stroke on my Sun Cat. Plenty of range with the 3 gallon external tank and there's room for a 6 gallon if you prefer. The Yamaha 4 has vibration and noise at 5.3 knots hull speed, but is well behaved at 4.7 knots. Between 1/4 and 1/3 on the throttle.

[cruz-in]

Dan, you had a Peep Hen? Any photos???
Bob23- the thread thief!
[/quote

Oh She was a beauty. PM me your email and I will email a pdf slideshow of pictures.

I traded her for the Suncat

[cruz-in]

Thanks everyone for taking the time to contribute. I am learning lots.

Let see if I can do a reasonable job of describing how I am thinking about doing the Bimini Dodger:

1) The Binimi would be two parts. The forward part would cover the forward 1/4 to 1/3 of the cockcit. The aft cover the rest of the cockpit.  They could be set up independently or together. Both Binimis would be free standing. You could use one without the other.

2) The dodger would attach to the forward bimini and the deck behind the hatch. Allowing access to the cabin while on.

I had a similar setup built for my Peep Hen and it worked very well.

More thoughts on the engine:

1) The Suzuki tested in the article was the old version of the DF5. Suzuki has just intoiduced a completely new version of the DF4/5/6 series. All three are basically the same motor, just different carbs.

2) The new DF6A ia by a long shot the lightest 4 stroke of its size. Wieghing in at less than 52 pounds.

3) So far I have not found anyone who has a review that addresses the noise and vibration of the new DF4/5/6A. Although Suzuki, in its product literature, talks about improvements in quietness. So I assume it is quieter than the old DF4/5/6.

5)

[Shawn]

"1) The Suzuki tested in the article was the old version of the DF5. Suzuki has just intoiduced a completely new version of the DF4/5/6 series. All three are basically the same motor, just different carbs. "

One really interesting thing about those engines is that they have an actual oil filter on them. Most of the 8/9.9 hp two cylinders (besides Suzuki) don't even have that. Too bad they didn't put the all in one tiller/controls of the 9.9A onto that series of engines.

Shawn

[cruz-in]

I understand that for many of the engines the 4, 5, and 6 HP are basically the same. Given this, why would one not chose the 6 HP verrsion and push the suncat at near hull speed with a lower throttle setting and (potentially) less noise and vibration?

[Shawn]

"I understand that for many of the engines the 4, 5, and 6 HP are basically the same. Given this, why would one not chose the 6 HP verrsion and push the suncat at near hull speed with a lower throttle setting and (potentially) less noise and vibration?"

Given the same prop all the engines would likely push the boat the same speed at the same RPM. The main (perhaps only) difference between those engines is the carb. The smaller carbs limit the total airflow of the engine which restricts top end breathing. You can see that in the max RPM differences of the engines.  Below maybe 3000-3500RPM or so the torque curves of all the versions are likely very similar due to them all being the same displacement and the airflow needs of the engine being lower. Above that point the smaller carbs will restrict airflow more and more which reduces torque (and therefor HP) and ultimate RPM. Peak power on the 4hp is 4500, 5hp is 5000 and 6hp is 5250.

I would get the 6hp and have the reserve power available (at higher RPM). That is assuming the engine has the proper prop to be able to reach peak RPM. If it can't the 6hp engine may really only producing 4hp at a lower RPM. HP = (torque x RPM) / 5252

Shawn

[cruz-in]

Thanks Shawn, Great explanation.

I have learned so much from folks on this thread.

Thanks to all for taking the time to respond. I am always amazed at the willingness of folks on the internet to help out like minded folks.

The new Suzuki 6HP and the Yamaha are the two front runners. Both cost about the same (just shy of $1500).

[Shawn]

"The new Suzuki 6HP and the Yamaha are the two front runners. Both cost about the same (just shy of $1500)."

Both would probably do well for you. They both offer charging as an option too.

Looks like Suzuki's USA site doesn't even have the info on the DF6A, it is still the old DF6 info. DF6A brochure here...

http://www.norboat.no/file/cd71121cd0cd21a184f00a2c6155642e/DF6A_4A_4sider/

On thing I notice in that is that the DF6A has a different prop than the 4/5hp models. It is a 1/2" more pitch on it at 7" instead of 6.5" pitch. They also have a 6" pitch prop which is probably better suited to a displacement hull. I haven't found what prop is on the Yamaha.

Yamaha looks like it has a nicer control layout as I think the shifter is on the handle itself. Both have more flexible storage positions. Suzuki is about 8 pounds lighter for the 20" shaft.

Shawn

[cruz-in]

Loooking at the Suzuki DF4/5/6A Brochure, page two, there is a noise versus RPM curve showing the DF4/5/6A is slightly quieter than the old DF4/5/6.  There is a band in the mid-range of RPM that shows a reasonable improvement over the DF6. I like this because this band is where I will be operating most.

The referenced article on the 5 HP test said the Suzuki and Yamaha were both the same noise level in the mid rpm range. As that test was with the old DF6, by deducttion at mid range of RPM:

F5 Noise = DF5 Noise   DF5 Noise>DF5A  hence one can conclude F5 Noise >DF5A Noise at mid RPM range.

Non - Algerbraic way of saying: If F5 and DF5 are about equal.,,,and DF5A is quiieter than DF5...then it follows DF5A is quieter in the mid rpm  range than the F5

[frank]

I posted a few pics of a dodger-bimini set up here (scroll down)

http://cpyoa.geekworkshosting.com/forum/index.php?topic=9054.0

Dodger stays up (center section rolls up for air flow when needed)
Bimini rolls up small when not needed.
Zips onto didger and has 4 SS clips that quicky attach to SS eyes on the boom gallows
Fast n simple.

Swapped the standard tank on my 4hp 4 stroke yamaha for a 6 gallon.(get one that fits compartment)
Tons of range and never felt underpowered....ever

Power cruising is fine....but the joy of the suncat is the ease of quick stepping the mast for those majic days......or motor sailing at less RPM on lighter wind days.

Fine lil boats!!!

Have fun!!

[cruz-in]

Thanks Frank,

Was carefuly looking at your picts. Really looks great. I would have to think thru the mainsheet on mine. It has the mainsheet/traveler mounted in the forward part of the cockpit. I really like it there. However, it makes the bimini dodger interface a bit tricky.

[cruz-in]

Interesting, using one of the tiller to engine connectios, would put the Tohatsu Sail Pro back in contention. Those devices/contraptions seem to overcome the issue with Tohatsu and not being able to lock in position...

If the 6 HP  E Stroke 2 Cyl yamaha does not work out, this may be worth considering...