siamjimi

Once again I am asking for more advice from you avid boaters.

I am not the rocket scientist about props - what pitch prop gives me the best fuel economy ? [ 38ft Scarab Twin 502's Bravo I's ]

What is the differences for props in general ?

This is my first boat of this size and want to make the right choices.

siamjimi

FYI - I am running long distances in this Scarab

akaboatman

iTrader: (1)

What are You running now. An what rpms. what kind of load? That is a loaded question. I will guess. 3800 4 blade. You asked for long dist. Lots of pitch if your not goiing through lot of idel no wakes. Artie

siamjimi

Thank you Artie [akaboatman];

WHAT I HAVE NOW - I have no idea what i have now - I have yet to put this boat in the water (been repairing the motors) and the props are in the storage compartment inside the cabin. I can ask the boat specialist working on my boat what i have.

My idea was to use the props i have as spares and buy myself a set of fuel economy props. I am shipping this boat to SE Asia and require a set of spares in the event I hit something and knock a chunk out of one of them - there are no prop shops in the areas i will frequent - all props would have to come from USA as far as i am concerned.

RPM's - ? - I will be getting a feel for the most economical rpm's once I get this boat into the water - I am thinking and have been told around 3,300- / 3,500- (?) is good for these 502's.

LOAD - I am dangerously assuming I will have around 11,000 lbs total weight when I am fully loaded with fuel, passengers, general items - the boat is 9,600 lbs dry.

SEA-CONDITIONS/WAKES - I am running offshore for long distances in varying sea conditions - preferably smooth to slightly choppy in the Gulf Of Thailand [GOT].

QUICK CONNECT / DISCONNECT (?) - Also - if you or anyone can explain the quick connect / disconnect types or prop nuts available - I need to remove them each time I put the boat into storage. I have heard there are a few different makes and styles - some being better than others.

the deep

iTrader: (8)

Thaistick ? Anyway brother Siam , prop your boat to run at the middle of your wide open throttle R.P.M.'s . For your 502's it is probably 4800 to 5200 . So if you prop it to run at 5000 wide open that will give you a nice efficient cruise speed at say 3300 . May i suggest Bravo 1 four blade props for a good bite on the water .

Griff

Just run the props you have and see how they work before you worry about buying new ones. I hope you realize that you will most likely be getting about 1 mile per gallon of fuel at cruise speeds.

FIXX

iTrader: (2)

hands down a 5 blade maximus will be the best prop for mpg..a friend use's 1/3rd less fuel in his foemuls compared to his bravo one 4 blades..as for quick change prop doohickys,,no such thing..just make sure you get some drive locks and prop locks from mcguard..

pstorti

iTrader: (2)

I have tried the maximus VS Bravo on two boats now and the bravo was better for mpg in both cases. The maximus grip the water much better than the bravo so you would have to try them and see. On the 28 daytona a hydromotive p5x was the best prop, I tested a lot of props 10+ On my current boat a 26 bravo has been the best overall and also for mpg, and I have tried everything from 27 mirages to 28 p5 hydromotives. On my current boat the 24 maximus was about .2 mpg worse than the 26 bravo, except when fully loaded with fuel, gear and 10 people then they were the same.

Unfortunately for you the reality is you have no knowledge of your boat how it runs and what the normal mpg is, and I am also assuming since they are 502's that you don't have fuel flow sensors installed so it is going to be hard to compare one prop to another. Ideally a 5 blade should be the best but in reality every boat is different and the only way to find the best prop is to try them out. I would start with a stock bravo 24p and use that as a baseline to compare against.

also never seen or heard of a quick connect for prop nuts