View Full Version : What size prop on a 2003 Bluewater 2350, with a DF 300

08-31-2011, 10:15 AM
I have a 2003 Bluewater 2350, a 2010 Suzuki 300hp on it. I am currently running a Suzuki 3x16x20 pitch prop in SS. It only tops out about 5500-5600 rpm and is quite slow to get up on plane. I have no doubt I am over propped. The next option in is the same prop in a 18.5 pitch, but from what I read that should only give me about 150 maybe 200 rpm, still not getting me to the 6,000 rpm max on this motor. FYI I tend to keep my fuel and water tank full, and don't usually travel light.
I am considering going to a 4 blade prop, hearing I will get a lower plane speed and more stern lift, whciH I think would both be a bonus. I don't run around at WOT, so the slightly lower WOT is not an issue. Most if my time is spent either idling or around 4,000-4,500 rpm. I don't see any 16" 4 blade props, so what happens if I go to a 15" prop. How do I compare the pitch on a 16 vs a 15 inch prop?
I belive in the newer 2350's they are mounting the bracket higher than they did in the 2003 models. I don't think my engine is much too low, but may be just a touch. While up on plane and trimmed I can walk back and see the top of the cavitation plate.
I also read somewhere that the 16" Suzuki props have alot of slippage, I find that hard to believe over a 15" prop, now drag there maybe a bunch, but slip??
Thank you for any input..

09-01-2011, 09:44 AM
Hey Kevin. I believe I have an 18" prop. 3 Blade. Not 100% sure of pitch. I was debating a 20" prop but opted for the faster plane and greater torque over the higher top end. The motor tops out at about 6100 RPMs. I think there may be a slight different between the prop I had before my lower unit got stolen and what they put on this time. In the past I would hit 50 - 52mph top end at around 5900 RPM. I was getting 48.5 mph with the same load the other day at 6100. I'd love to experiment a bit with other props.

09-03-2011, 08:25 AM
Chad. I just found a 3 blade 16 inch diameter (which is more than likely what you have, possibly a 15", for sure not a 18") in a 18.5 pitch. It should have been delievered yesterday, and I get home this evening. I will run it sometime this week. Willl let you know what I Find. I am hoping to get similar results to what you were seeing, but don't think it is going to happen. I honestly expect it to up my RPM about 150-200 rpm which won't get me to 6,000, buut atleast hoping it will get me on plane reasonably. I have a feeling I will be playing with props for a while, hoping to try a 15" 4 blade at some point. I managed to find the prop I bought at a shop that buys left overs and I got it for about half price, so it was not as painful, and why I was willing to try it.
Will let you know what I find.


09-07-2011, 10:22 AM
You were right Kevin. My bad. I checked it yesterday and it is a 18.5 pitch 16" 3 blade prop. However, this week I am swapping it for a 20 pitch 16" 3 blade prop. I will let you know if I see an improvement in performance.


09-08-2011, 05:18 PM
Pretty funny. I just put the 3x16x18.5 on my boat and it runs much better. Need to test it again with my typical fishign load on it. I was going to offer to bring my 18.5 and 20" props down and let ya try them both, atleast to give you somewhere to head. If that 20 works for you we should have just traded props... OH well I got my 2nd prop for a steal from a liquidation place. Found it through ebay. IT was $285 shipped, taxes and all. NOt bad for a SS Prop.

09-08-2011, 09:45 PM
Now I am thinking I may need to stick with the 18.5. But I am a little puzzled why I seem to have lost a few mph and gained rpms with what seems to be the same prop. I posted what prop I had... on the old forum! Damn you archives!!!

09-09-2011, 09:00 AM
Chad if it helps I am pretty sure you had the 3 16 20 on it before. Cause I had asked you when I first got my DF300 and I was pretty sure we had the same prop and I was wondering why you and I were seeing such differant numbers. I am pretty sure BW has mounted the brackets at differant heights on differant boats and it probably changed around the time the 4 strokes started coming out, which could make a huge differance. Run that 20 and I bet it is close to what you were seeing before. I am pretty sure my boat is the odd ball... Even with the 18.5 2 people and a fair load I was only seeing 5750rpm. Still can't find 6 grand. I am looking forward to trying it with a normal fishing load in it. The other day when we went out it was just 2 of us and we were just Snook fishing so didn't run a whole lot and left most of the heavy tackle at home.
Good luck, look forward to hearing results.


native son
09-11-2011, 08:07 PM
Hey Kevin, went down to the marina and checked for the holes to move motor up, I got 2 to go, so I thought I would take a quick ride since I couldn't find anyone to fish with, never really noticed the RPM issue, ran it WOT, which I never really do, Im retired and not to get in any hurry, I run it like I own it!!! anyway could only get about 5500 out of her, never trimmed it up, but one person, very light and with the 15 1/4 X 19, three blade. now what do you expect, more/less prop, move motor up ? too many issues with not knowing what is the next step. I couldnt look back a the prop and see where the plate was running.Maybe my next move after suggestions, will be to call Paul at BW and see what he thinks, you know those engineer types, always trying to get the most out of nothing.....any input would be great.. thanks

09-15-2011, 10:23 PM
I think the best move would be to see where the caviatation plate is when up on plane. Not when your by yourself, but when you have company you trust to drive the boat and not send you swimming. Looks like you probably could gain some RPM, but without knowing exactly what your red line in that specific engine is I may be wrong there too. I would also say test it with your typical load on it, as that is what you probably want to prop it for. As for calling Paul I doubt it will do you a ton cause it appears they have mounted these brackets at diffferant heights, and it looks like the heighth changes came in around the time the 4 strokes were showing up. I know the newer boats are mounted much higher than mine is. For quick reference take a look at the gap between the bottom of the tuna door and the bracket, you will see quite a variation between differant boats. I also know they have used a couple of differant brackets some having more flotation in them than others for the 4 strokes.
Honestly I think there are too many pieces to this puzzle to be able to say this is what Joe has so everyone needs the same prop.
I would start with loading your boat average, then check where your cavitation plate is, then go from there. If it is too low in the water try raising your engine. If it looks right try changing your trim. Mine seems to run best with the trim tabs about half down and the Suzuki gauge reading around 30% trim up. Now my old Yamaha engine used very little if any up trim, but this Suzuki almost requires it, and you can watch the efficiency get better as you trim it up tojust before it starts to porpoise. I would for sure work on trim and engine height before I would go buying any differant props. Now if you can borrow a prop or two than go try them out. If nothing else it will give you a place to start when you figure it all out. Unless you have the equipment raising the engine can be a real pain, but if you have the equipment it is not hard to do. I wish I had it but I don't.
Good luck and I hope I have given you some helpful info. What I would avoid doing is buying a differant prop now to find out you need to raise or trim your engine differantly which could lead you to needing a differant prop later.
I know I would probably raise my engine one more bolt if I had it to riase it. Although with watching it running it looks to be very close to where it should be, plus I am willing to loose a little if I know in rougher water my prop is going to stay connected to the water. I have yet to blow it out YET.... My main goal right now is to be able to get up on plane a little quicker and find my upper RPM limits, not that I will run it there (I also drive it like I own it), but that seems to be the best gauge for efficieny in the range I do run it in. If you aren't making full RPM then your engine is working too hard to do what it is doing and that will burn lots of gas, plus you won't get up on plane. It is all a big vicious cycle and one I for sure have not figured out.
Good luck.

09-16-2011, 12:29 PM
Hey Kevin. When I picked up the boat this week, they told me the 20 pitch props are on back order, so I am still running the 18.5. Hit 6,200 RPM @ 49.5 mph with 100 gallons of fuel and just me on the boat. Still feels like I have room to run a slightly higher pitch. Maybe sometime in the coming weeks we can meet up to compare how my boat runs with the 18.5 and 20 compared to yours? Would be interesting to see how the variations BW made over the years effect performance with the same power.

09-18-2011, 10:51 AM
Anytime.. I am off all week this coming week. I airline home today Sunday, and will be home till Saturday sometime. Hoping mother nature cooperates for a sword fishing trip about Thur night. Let me know if and when your available..
Kevin (772)233-6698