South Bay 522RS top speed

[Ozark Bob]

Hi all,

I am new to the forum and soon to be new to tritoons. Tomorrow I am going to test drive a 2014 South Bay 522RS with a Mercury 150 4 stroke. The boat is a tritoon with the 3/4 length center tube and full under skinning. My question concerns the top speed. The owner says it's 32 mph per the on board GPS. From what I have been reading 32 mph sounds a little low for this set up. What do you all think?

Thanks,

Bob

PS. When I get a minute I will introduce myself in the Welcome Forum.

PPS. I forgot to ask. This boat has the Murphy display which includes the tach, trim, fuel, hour meter, GPS speedo, depth, water temp etc. I am not familiar with this display and info is pretty scarce on the web. I am a little nervous about having all my eggs in one basket so to speak. Any feedback?

[jimbo21165]

Hmmm......sounds a little low, but depends on weight, balance......

My tub is 25' long, two tubes with Merc 150 4 stroke........I hit 36 GPS with me and another bud on board.......35 gallons of gas, he and I 300 lbs each, and a 60 qt Yeti full of adult beverages......

[FLOUNDERPOUNDER225]

my 2015 Berkshire 231RFC (Same boat as South Bay) 23.9" Length, 2.75 Performance package (3/4 middle toon) with 150 Yamaha 4-Stroke, 15 Dia. X 14 Pitch Stainless Enertia Prop turns 5900 RPM @ 39.+/- MPH light load, 2 people. regular day with coolers, 4 0r 5 people 35/36 ish. this is GPS true speed. your boat is pretty much identical, you need to closely watch WOT RPM and associated speed, should be pushing the 6000 RPM range +/- a little.

On your murphy gauge: there is not an internal GPS on that, if there is no GPS then the reading you ar seeing is probably from the pitot tube speedometer which works from water pressure as the engine moves through the water. Purely useless indicator IMO. If you have a GPS that plugs into the cig lighter in a car like a garmin, you can use that on the boat and bring up the speed on that.

[Strake]

Welcome to the forum, and getting a Tritoon !!!

We have the same family (manufacturer, Forest River Marine) of boat, a Berkshire 233RFX STS Series with full length center tube, lifting strakes and a 200 Yamaha.

If the top is not open, with 2 people and less than a half a tank of gas, the best we have gotten 42 MPH ..... GPS. We have a 14.5 X 15 pitch Yamaha Reliance SS prop. Most times, when I open it up for a minute, I am able to get 40 mph. I only get a max of 5800 rpm. I also noticed our engine is mounted in the LOWEST mounting hole.

As for the Murphy gauge, ours does not include a GPS speed, but I see in the brochure it is an option. I have a GPS built into my GARMIN chart plotter.

I am guessing this boat is used? How many hours are showing on the Murphy gauge? By the way, that is somewhat difficult to read as it's in black font that is small and overlaid on a dark gray section of the gauge right at the bottom lower left corner of the gauge.

[ron nh]

It's definitely slow, Either prop or engine height. The Murphy touch screen is awesome.

[Ozark Bob]

Thanks for all the responses.

FlounderPounder225: Strake is correct. GPS speedometer and Map is an option, along with depth and water temperature. I saw the original order sheet to verify these options were included. BTW. My buddy from Gulf Breeze is here, Lake of the Ozarks, visiting and is going with me tomorrow to test drive the boat. Small world.

Strake: The boat is indeed used but very little. The owner says it has 50 hours on it. I will verify that tomorrow.

From everything I have read/seen I think this boat should run 35/36 mph which I would be happy with. Not sure If I would be happy long term with 32 mph. I know, again from reading this forum, that the engine height and prop selection can make a 3-4 mph hour difference which would get me where I want to be. I don't mind taking the time and spending a little money to get there if it is achievable.

[ron nh]

What size is your prop? and what RPM's are you seeing? you can access GPS on a cell phone. If you think 32 is accurate get the same size prop as flounder pounder. And congrats, that's a nice boat.

[bradm]

Our previous boat was a 2012 South Bay 522 CR with 175 Suzuki. We had full third tube. With 2 people full fuel and top up ran 39 to 40 on GPS. 32 indeed seems slow for similar boat with 150. Maybe dirty bottom wrong prop or wrong engine height.

South Bay is a great boat. We sold first one and bought another.

Good luck

[Ozark Bob]

What size is your prop? and what RPM's are you seeing? you can access GPS on a cell phone. If you think 32 is accurate get the same size prop as flounder pounder. And congrats, that's a nice boat.

I haven't driven the boat yet so I don't know what the rpms are at WOT. I will find out tomorrow when I drive it, Same on the prop. I know the Mercury 150 4 stroke redlines at 5800 rpm. The owner showed me a picture on his phone showing 30 mph at 5200 rpm. Not sure of how the boat was loaded or if he had it trimmed properly. Again, I will find that all out in the morning.

Thanks again for all the responses

[Ozark Bob]

Hi Everyone,

Well we got to drive the boat on Saturday and the owner was correct, 32 mph was indeed top speed no matter what I tried. I will say we had four people on board, 2 small and to regular to large and very little fuel. While I was a disappointed in the top speed we liked the boat so much we bought it! We hope to pick it up next week, in time to cruise the lake and see the fall colors. Currently I am in the process of converting the lift on our dock from a v-hull setup to a tritoon.

Regarding the performance I feel that we might get a little more speed if I play with the engine height and prop. We tried to check the engine height by looking at the cavitation plate while at full speed with the engine trimmed to achieve the best speed. It looked like the engine could be moved up one notch, the plate was just below the water line. I did notice, however, that in a hard turn I had to trim the engine way down to keep from cavitating. What does that mean? I had some problems figuring out the prop size but I think it is a 14". The prop is as Power Tech, not familiar with them, and the numbers on it where OFS3R14PCL200. I would be interested in hearing your thoughts. Here are some specs:

2014 South Bay 522RS
Mercury 150 4 stroke
3 toons with 3/4 center tube
Lifting strakes on the inside of the outer toons
Top Speed 32 mph at 5300 rpm.
30 mph at 5100 rpm.
39.5 hours total time

I was a little concerned about the Murphy Gauge but after seeing it work I really like it. It has everything on one screen, GPS speed, RPMs, trim fuel, battery, hours. On a sub screen it has a map. I'm a gadget guy and this thing is really cool

Thanks again for all your input. I'll post some pictures when we get it home.

Bob

[bradm]

Congrats on purchase. Looking forward to seeing your pics. I believe you can find some more speed. South Bay is a great boat!

[Bamaman]

You'd probably need to leave the engine height where it is for now since you're ventilating some.. Others with the Merc 150 FourStroke are reporting 38-40 mph commonly, and that motor doesn't lack for horses.

Your current prop is a 14 pitch and the prop is not an off brand. But your engine is low on rpm's. Your engine most commonly would use a 14 or 15 pitch prop, and I cannot see where you'd go lower than 14 pitch.

You might see if the original dealer would allow you to take 2 Mercury Enertia props to the lake (14 & 15) and return one or both if performance is not improved. In my eyes, the boat shouldn't have been delivered without it been performing at its full potential.

You could also call the manufacturer customer service to say what prop they recommend. My manufacturer build sheet spec'd out the propeller, and the dealer had to swap props when he stuck the wrong prop on mine.

[mpilot]

I couldn't find a test with the 150 but I did find it with a 200 pro that ran 39.5 so your speed may not be that far off. Your rpms are borderline in range though so you may want to consider dropping in pitch or diameter depending on what size prop you have.

[FLOUNDERPOUNDER225]

I don't understand the low RPMs with only a 14P prop. Going to 13P might bring the RPMs up, but definitely going to lose speed. My 14P Enertia holds well in a turn, and that's at just a hair above half on the Trim gauge, never a need to trim down in a turn. Now the Enertia is a MUCH larger prop dimensionally, you can see it in the blade rake, the blades would dwarf a powertech prop. I personally feel the powertech is not enough prop for the boat, your losing too much thrust, some cup on the prop might help, but as someone suggested, if you can get the dealer to get you a 14P Enertia, you'll be amazed at the performance. My engine is on Next To The Highest possible engine height. It was on the middle originally, I raised it one hole.

[Ozark Bob]

Hi Everyone. I finally got the boat home and in it's new home. We love the new boat and are looking forward to years of enjoyment.

I have had a chance to do a little more experimenting with speeds at different throttle settings. Here is what I have found so far. All the speed are GPS and the trim set at best rpm/speed which seems to be a little less than 1/3 up or 30 on the digital readout.

3000 rpm = 15 mph
3500 rpm = 19 mph
4000 rpm = 23 mph
4500 rpm = 26 mph
5000 rpm = 30 mph
5300 rpm = 32 mph

After doing a lot of reading I believe the engine is set to low. It's on the second hole from the top. I have a lot of spray from around the engine making it very hard to see the anti cavitation plate but I'm pretty sure it buried. I have attached a picture of the engine at about 5000 rpm. I also have a short video but can't figure out how to upload it. I also attached a picture of the new boat.

I am planning on raising the engine at least 2 holes but would like to hear your opinions before I do. Once I get the engine height set I need to figure out if I am running the best prop for my set up. It currently has a Power Tech OFS3R14PCL200 which is 15.25 X 14".

Look forward to hearing what everyone thinks.

Thanks,
Bob

PS. Sorry the pictures are sideways. I tried turning them but it didn't work. I'll figure it out someday.