Pontoon Boat & Deck Boat Forum

Sorry, I posted some of this info on a previous thread before I found this one.

"We took delivery of our Cypress Cay 230 Seabreeze with a 115 Merc Command thrust on it. With four people and about 15 gal of fuel we ran through our break in period and could only achieve 5000 rpm @ WOT and checked the speed via GPS at 22 to 23 mph. It would shoot out of the hole very strong but between 3/4 and full WOT there was no increase in speed and it only seemed like the engine was just making more noise and the motor did not feel like it was pulling. I ran the part number off the prop on my boat and it came up with a 16 in dia 16 degree prop. I called Cypress Cay and they indicated the boat should have come with a 16 x 13 prop and they will replace it. Just waiting on the dealer to pull it off and send it back now. Kinda curious what I will see for performance or speed increase now?"

Any ideas what kind of reaction I can expect with a 13 degree prop now? I would be really happy if I could get the RPM's up to about 5700 and the top speed up to about 30 mph. Just wandering if thats possible.

Thanks,

Kip

I thought I'd post some info here with respect to boat & prop. I need to collect more data but this is what I have for now.

2015 Sylvan Mirage Cruise 8522 LES RPT PR25 Package
Outboard: Yamaha F150XA (about 25 hours)
Prop: Solas "New Saturn" 3531-145-15 (Stainless Steel, 3 blade, 14.5" diameter, 15" pitch)
60 gallon gas tank was about 3/4 full
4 people onboard (2 up front and 2 mid)

37 MPH, 5700 RPM was WOT, trim was all the way up

TCROW-
I finally got a picture of the prop

and the final drive:

As I learn to drive the boat, I've approach 5100 rpms at 32 MPH loaded at WOT.

I'm not sure what the max rpm is on this motor, but I think there's more to be had.

I will soon be under skinning......

Your thoughts and insights are anticipated.

Well, I put a new Mercury Black Max 14 degree prop on today and tested again. This time we could get to 6000 rpms and speed on GPS maxed out at 25 with it trimmed up. Still seems like there's more in it but I'll be darned if I know how to get to it.. Any thoughts?

So I went to my local Tracker boat dealer today just to inquire about the prop blowing out and the lower than expected RPMs. Before I could finish my sentence, one of the maintenance techs takes me over to an Identical boat and shows me a V shaped plate thats welded below the transom. Tells me to cut it off or bring it by and they will do it for me. I guess tracker sent out a tech bulleting for this very issue on boats equiped with the 90hp command thrust and higher. Evidently, others were having this issue and it was narrowed down to V plate causing "dirty water" (bubbles) to get in front of the prop, hence the cavitation.

I was also told by the service tech that after doing this, they took an Identical boat as mine to the lake and they said it hit 36.5 miles per hour and zero blow out! I can easily hit 32 MPH now but I cant trim the motor up more than a schoch..

I'm skeptical, but I'll be sure to follow up once I get mine cut off and the results. I'll try and take a pics as well.

Mike

below is the "V" plate That needs to be removed.

I cut that V-gard off my motor pod and while I was able to get more use of the trim I did get a massive amount of water now boiling up around the motor. It is not causing me any issues but it is somewhat unnerving to see the motor looking like a hand mixer running in a blender.... Only when I'm lightly loaded can I trim up past 1/4 on the gauge to which the boiling water does then disappear but there is no more speed to be had when trimming from 1/4 to 1/2 for me....

TeeCRO,
I'm skeptical but if the cavitation is diminished, I'll be pleased. The toon already does 30+ WOT (with TT trim) and I'm fine with that. Anymore than TT trim and she blows out.

So I removed the plate that I described in an earlier post, here's my finding.

Boat handles (Steers great)better, I can trim the motor over half way and no washout. Steering is crisper, but top speed has been effected. I was only able to reach 27MPH, were as with the plate I could get 32/33 MPH. RPMS at top speed was 5000. I did notice that at 3/4 throttle I was at 5000 Rpms and the same at full throttle .

Think its time to drop my pitch by 2 and go with a 15x15P aluminum prop until I get it dialed in and then a SS one.

I hope I am not thread jacking. If I should move this to it's own thread just say so.

I could use some help on selecting a new prop for my boat. The current prop I feel is over pitched. The motor seems to lug at lower rpms and it's sluggish get the boat to cruising speed. It also ventilates, cavitates, or could be a spun Hub. Often above 3/4 throttle it will lose power and rpms will climb. I did hit small rocks in the shallows last week and this this issue started after that, the blades were pretty beat up to begin. To complicate Prop selection the boat does not have a tachometer (one is going to be installed shortly). With just me and 12 Gallons of gas on windless day and glassy water I was GPS'ing 25-27 mph.

The Boat is a 20' Playbuoy powered by a 1974 Johnson 85HP. the prop that is currently installed is a Solas Amita 2411-133-17 Aluminum Boat Propeller. 3 Blades, Diameter: 13 - 1/4, Pitch: 17

I don't care much about top speed. We like to cruise around 1/2-3/4 throttle. Slow speed handling / cruising gas performance is most important to me. So what would you suggest?


for now I'm going to order a 13X15 and once the tach is in get an idea of where to go from there.

Info on my tritoon:

27' (with 25.4' toons) Regency 254xp3 2014 model
2007 Merc Verado 275hp Simonized
1.85 gear ratio
15P Enertia
6200RPMs
46mph by GPS
strakes on both sides of all 3 logs.

Getting ready to prop the new Manitou. I have 4 props to try, after raising the motor 2 holes. Here's what we have to load. Props, adapters, torque wrench and 1 1/16 socket, extendable magnet, needle nose and side cutters. Chunk of 2X4 and the holy grail of prop testing... The Prop slip calculator!
Water is too cold for deep water swaps, so I'll have to beach and spin...
Fun Stuff!!! Really!

GOOD LUCK!

I was wondering exactly how do you tell what pitch you need for your prop on a 90 horse motor?

[quote="Pixiedust"]I was wondering exactly how do you tell what pitch you need for your prop on a 90 horse motor?[/quote]

Simple answer is you don't tell EXACTLY what prop... You really need to provide info at to what size boat, pontoon or tritoon, motor size as well as 2 or 4 stroke and manf recommended wide open throttle, current max speed and RPM at said max speed and what size prop currently in use... There are prop calculators that will get you really close but there is no exact science to it. www.mercurymarine.com has a pretty good calculator in their prop page.

Or you take a WAG "wild ass guess" at 14" x 13P 3-Blade for a 90 HP on a pontoon...