Merc High 5 Props

[arvan]

Wondering if I went to a Merc High 5 what pitch I would most likely need?
Boat is a 18ft bowrider with a 4.3 Alpha 1. Currently has a Merc 14x20aluminum 4 blade prop on it. WOT rpm is 4600 with a top speed of 47 mph.
Boat weights 2300lbs. Not interested in top speed as much as in all around watersports. I've rode with several buddies who have them on their boats (19 ft /V-8's) and they seem to be a good performer. Any and all suggeestions welcome.

 

[rallyart]

Re: Merc High 5 Props

I would try to find a prop shop that will let you try several props and exchange them if they are undamaged. I found that the Vensura 4-blade was better than the High 5 on my 18'. The High 5 has a good reputation for watersports though.
From the info you provided it looks like you could go to a 19" without much issue but if you go lower you will have to watch the RPM and try to keep it from going above 4800 at WOT. Try a 17" while you're at it. The hole shot will be impressive but you really have to watch WOT.

 

[arvan]

Re: Merc High 5 Props

At over 800 bucks no one wants to really let one out for trial. Buddies props are 23 pitch and thats too much prop for my rig. I figured 19 might be the way to go. Was hoping someone on here was running a similar boat/engine combowith this prop. What pitch are you running with the Vensura.

 

[rallyart]

Re: Merc High 5 Props

21". I opened the vents with a 1/4" hole to increase my prop speed on startup and get the boat up faster. My top speed went up from an old SS 3 blade 21" and starts were much better. They make plugs for the vents of different sizes but I just drilled my closed ones until I got up to a size that did not make much subjective change in my acceleration.

 

[stimps]

Re: Merc High 5 Props

I have a four winns horizon 170 with the 4.3gl 190hp engine and use a 23 pitch high five for wakeboarding. Fantastic pull out of the water and still get nearly 50mph top speed so cruises well for normal stuff. The high five is a smaller diameter so does not appear to need to drop pitch size for the extra blades. I would use a 21 or possibly the 19 on yours but would need to watch the revs.