4 Blade Trophy Plus on a Merc 115

OK, I read the "Read this first" section and the other Stickys so I think I am ready...

1) I want to get a better hole shot. It is a bit slow to plane especially with a full tank and live well (also in the back).
2) I have a SS Mercury Laser II (pn#48-16992).
3) Specs say it is 13.5" diameter and it is 22P.
4) WOT is 5150 (5250 is max) and I get 52mph off the GPS.
5) 2004 Mercury 115 ELPTO 2-stroke.
6) 2004 Nitro NX750, 17.5' and guess on the weight at about 2000 pounds.

I can get a SMOKIN deal on a Trophy Plus 23P and was thinking that would give me a better hole shot plus hold plane a little better at slower speeds. Also, I occasionally go out to pull a tube and the 22p Laser II just will not get up on plane. I know that I might give up a little in top speed but that does not bother me at all. I am a little concerned the 23P 4-blase will drop my RPM.

THANKS!

Re: 4 Blade Trophy Plus on a Merc 115

Yep if you wanna go to a 4 blade look for a 21" pitch

seems odd to me that a 50 mph boat has trouble getting on plane.... are you trimming all the way down first? I'd think that boat would plane easily with half that HP.

might consider smart tabs.

Re: 4 Blade Trophy Plus on a Merc 115

The boat planes fine with an empty livewell and a half a tank of gas. If I have my two boys, and all the tanks full it can be a dog. I may still buy the 23p Trophy since it is only $150 and is in new condition then try to trade for a 21p.

Re: 4 Blade Trophy Plus on a Merc 115

I ended up buying the prop and took it out for a test run yesterday. It was definitely a change. The biggest change was how sensative the Trophy is to trim positions. Just one click either too far up or down and there was a lot of feedback in the steering. The Laser II was much more tolerable of trim changes. The hole shot was pretty good but not quite the improvement I'd hoped. As expected, WOT came down to 5050 (from 5150) and top speed (GPS) dropped to 48.5 mph. The bow lift was not quite as high as the Laser II but I expected that and it was MUCH smoother. I'll probably play with the PVS sizes and see if that will improve either one.

Re: 4 Blade Trophy Plus on a Merc 115

himmelrr said:

I ended up buying the prop and took it out for a test run yesterday. I was definitely a change. The biggest change was how sensative the Trophy is to trim positions. Just one click either too far up or down and there was a lot of feedback in the steering. The Laser II was much more tolerable of trim changes. The hole shot was pretty good but not quite the improvement I'd hoped. As expected, WOT came down to 5050 (from 5150) and top speed (GPS) dropped to 48.5 mph. The bow lift was not quite as high as the Laser II but I expected that and it was MUCH smoother. I'll probably play with the PVS sizes and see if that will improve either one.

Click to expand...

I assume PVS means that the Trophy is ported and has plugs. With that assumption, the larger the hole the better the hole shot assistance (the more the prop will ventilate achieving desired rpm's much faster. Additionally, having had a BBoat that I water ski'd behind, I was running a Laser I which was ported (before they had sizing plugs) and the ports in the prop were a real asset in getting my body up on the water and the boat also as it was a Ranger deep V.

Problem with the larger holes that at high trim positions and in turns or rough water you can bget some blow out, but you can eliminate all or most of that by tucking your trim in till it quits blowing out.

I was going to ask you if you tried tweaking your LII port holes but you had already bought the Tempest.

Other nice things about the ports is that once you get up to speed, they seal off and are essentially out of the circuit and you get the full benefit of a higher pitched prop unless you have the blowout mentioned.

I just checked and you are running in the middle of your recommended rpm range (4850-5250) with that engine prop (both props) combo. I am running a 90 triple of that engine/vintage on a 850# tin boat + engine folks and gear. The engine has a 2.3 gearbox (yours has a 2.0), am running a Ballistic XP 24P at 5800 rpms (5000-5500 rec. range) at 48-49 gps. I have a stepped hull such that at WOT I have a small wetted area which translates into low drag. I don't know what you hull looks like nor what your wetted area is at WOT. Otherwise seems to me that you are right where you need to be on prop, and rpm's. On hole shot, the flatter the hull is at the transom the faster the hole shot. If yours is a deep V then you should expect a slow hole and if it bothers you trim tabs might be in order.

HTH,

Mark