Other than that, you will lose a bit of top speed but gain speed and acceleration in the low to mid-range. My experiences would suggest that the High-5 props run slightly higher revs than other props of the same pitch, so be careful in your selection - especially if you are already close to the rev-limit. A 19" High-5 prop was noticeably faster out-of-the-hole but hit the rev limiter, achieving 48.5mph 5,000rpm and 0-30 in 7.0 seconds. Performance with the 21" High-5 was very similar but at lower revs, achieving 49.1mph at 4,650rpm and 0-30mph in 7.5 seconds. The Maxum (bought new) came with a 19" Vensura 4-blade stainless prop, which seemed a good all-rounder, achieving 49.2mph at 4,800rpm (again, the recommended WOT range was 4,400-4,800rpm) and did 0-30mph in 7.5 seconds. I did not use the aluminium prop enough to have any meaningful comparison with regard to acceleration but what was immediately apparent was the impressive smoothness of the High-5 and, as said above, the increased grip in turns. Fitting a 21" High-5 prop brought the revs down to 4,800rpm and still achieved over 40mph. The Monterey came (second-hand) with a 19" 3-blade aluminium prop but was under-propped and hugely over-revved to about 5,300rpm (WOT range 4,400-4,800rpm) doing about 40mph. However, I have had a bit of experience with High-5 props on two boats, firstly a Monterey 180 Edge fitted with a 3.0L 135hp Mercruiser and a Maxum 1900 SR3 fitted with a 4.3L MPI 220hp Mercruiser. You don't say what boat / engine / drive / propeller combination that you are currently running, so I hope that what follows is relevant to your circumstances. The aluminium prop would just ventilate like crazy at the same speed, enough that the engine over-revved and you had to slow down.Īll this is of course relating to a much smaller boat/engine than yours and although Mercury say the HighFive is suitable for 75HP and up I think it probably needs a big, torquey engine to come into it's own. You could feel your neck muscles tensing with the G-forces. With the HighFive I could throw the boat into a tight turn at pretty high speed and it would just grip and go round. The Laser II is almost as good and both are way better than the standard Quicksilver aluminium prop. I bought a bunch of various sized plugs but never got round to trying them because they are difficult to swap with the prop on the boat.Įven though the HighFive was slower on both acceleration and top end I was still loathe to swap it out because the grip it gave on cornering was phenomenal. We tried the prop with no plugs and the boat could not plane off it just sat there 'wheel-spinning'. Mine came with the 'medium' plugs and worked quite well. The Laser II came with the later version of PVS where you can swap out plastic plugs with different size holes (and hence gas flow). As the boat moves forward the water flow stops the gases escaping, the prop grips and the boat takes off. The idea is the blades grip less during initial acceleration, allowing the engine to spin up into it's peak power range. This features holes in front of the blades in order to allow the exhaust gases over the blades at idle. The HighFive came with an early version of the 'Performance Vent System' (PVS). An 18P Vengeance I tried gave even better acceleration but the engine was over-revving flat out. This gave me better acceleration than either of the two previous props and a top speed of about 45mph. I replaced the HighFive with a 20P Laser II, modded to 19P. Acceleration was about the same as the previous 21P aluminium prop and top end was down from 47mph to about 42mph. I had a HighFive 20P (small hub) on my Fletcher Arrowflyte/75HP Mercury.
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