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rastadr
09-28-2016, 08:20 AM
Ive tried every 3 blade known to mankind. There must be a 4 blade that does it better. Anyone running one?????

Ghost
09-28-2016, 09:25 AM
What would be better to you? Are you looking for WOT speed, cruise speed, some sort of handling improvement, hole shot, other?

Pat McPherson
09-28-2016, 09:32 AM
I run a Rev 4 on my 22 but not sure there will be the same benefits on a 16' boat. Always worth testing though...

mattyboy
09-28-2016, 10:50 AM
the 6 cyl 16 usually run pretty well with a better balance than a v8 and usually don't come with the handling issues the v8 have provided the v6 is pushing around 220 hp or more. should be a mid 50s to high 50s boat.

but as mentioned without knowing the issue or the numbers speed pitch and ratio there is no benchmark to start with.

rastadr
09-28-2016, 11:01 AM
ghost. I want a better hole shot, better acceleration and more top end...don't we all???? The boat lives in the florida keys so its all about top end. its a 4.3 so after it planes off it stays at wot till its time to stop. I really need someone with the same boat actually running a 4 blade to answer me.

Ghost
09-28-2016, 11:04 AM
ghost. I want a better hole shot, better acceleration and more top end...don't we all???? The boat lives in the florida keys so its all about top end. its a 4.3 so after it planes off it stays at wot till its time to stop. I really need someone with the same boat actually running a 4 blade to answer me.

FWIW, I'd bet a lot that you won't find any 4-blade that gives you more top speed than the fastest 3-blades.

woobs
09-28-2016, 09:02 PM
I really need someone with the same boat actually running a 4 blade to answer me.

Although, not a Donzi... I have a 4.3 in my 2,200 lb., 18', 20* deadrise boat that was dyno'd at 236 HP/ 274 TQ. It's mated to an Alpha with a 1.62:1 gear and a 19p High Five , 5 blade prop. My best GPS speed is 51.8 mph @ 4,500 rpm. The boat jumps up on plane in just about its own length (even with 5 people aboard). It handles beautifully in all conditions and corners like nobody's business! Fwiw, the boat has no lifting strakes.

Now, I think I have too much hole shot and would like to trade some for more top end. To do this I have been looking for a 4 blade prop in the same pitch for some time....unsuccessfully. The problem is diameter and blade surface area. The High Five is 13.25" in diameter. Most 4 blade props are 14" or larger. You would think by losing a blade I could gain 1-200 rpm but, NO! The increased diameter comes with more surface area and I actually end up losing RPM to a prop that's harder to turn. In one case (19p Solas HR Titan 4) I actually lost 800 RPM.

I have only found ONE small diameter 4 blade prop. The 19p Trophy Plus is 13.75" in diameter and is similar in rake and blade shape to the High Five. Unfortunately, I have not been able to find an affordable used one or, one to test... and at the price of this one, I'm not buying another new untested prop even with an educated guess.

I believe if this 4 blade prop can get me 200 RPM that will equate to around 54-ish mph. The Trophy Plus is a good handling prop by all accounts and I believe it will not cost me too much there. Further, if this set-up were on a Donzi 16 I believe it would be faster across the board from hole shot to WOT.

Anybody have a RH 19p Trophy plus (15 spline) sitting on there bench with nothing to do?

smokediver
10-09-2016, 10:12 PM
If you are looking for top end , a laser 2 is one of the fastest prop for that set up.

Turbochad
10-10-2016, 10:27 PM
ghost. I want a better hole shot, better acceleration and more top end...don't we all???? The boat lives in the florida keys so its all about top end. its a 4.3 so after it planes off it stays at wot till its time to stop. I really need someone with the same boat actually running a 4 blade to answer me.

You need a small block chevy. Then your boat will have more hole shot, better acceleration and more top end, but as others have said the handling will be worse (I hear). I have a modified 302 (340hp) in my 16 and I run a high 5 19p for pulling and a 23p for speed and general use. I don't think you will find a four blade to be faster on top, more of a compromise between acceleration and top end speed.