Xpress Performance Questions

[Duckmarshal]

I recently purchased a 2003 18 foot Xpress Hyperlift hull with an Evinrude 115 and a Power Tech 20 degree prop.  My GPS shows my max speed at about 42 MPH which seems extremely slow and not what I expected.  I sold a 16 foot Xpress duck boat with a 40 Nissan last year that ran 32MPH.  I just added a Hydro Dynamic 6 inch jack plate and fished with it today in a local tourney but with the tourney and high wind never checked for improvements.  A buddy is helping me and thinks moving to a 23 Renegade prop will boost top end performance.  What can you guys tell me with experience running similar Xpress boats?  I'm not trying to build a racing boat, but want to get the best performance possible out of what I've got.  Thanks in advance.     

[Buzbait88]

Whats your RPMS and water pressure at Wide open?  THats going to help us tell alot.  I think you should be getting more than 42mph, probably closer to or above 50.  WIthout knows the RPMS or Water pressure its tough to tell.  Is your current prop a 4 blade prop?  ALot of times the aluminum boats with smaller motors run better with a 4blade prop because it lifts the back of the boat up a little bit and helps hold the bow up.  a 23 might be to big, but worth a shot.  I would think a 21 or 22, but I'm no expert.

[wvbassangler]

I would buy a 25P three blade,  them tin boats run a little better with a three blade.   I know a guy who has a 115 on a fiberglass nitro and it will run around 55.
I would call Xpress and ask some questions on getting this boat set up I know sometimes it takes some time on the xpress.  Some guys are getting some great speeds out of them.

[Duckmarshal]

Hopefully we will get the winds here in LA to die down next weekend so I can do more testing.  How do I check the water pressure?

[wvbassangler]

Hopefully we will get the winds here in LA to die down next weekend so I can do more testing.  How do I check the water pressure?

You should have a water pressure gauge on your console

[BOATS]

Did you ever figure out the issue?

[Les Young]

Doesn't sound to far off for a Powertech prop. They actually like Turbo props pretty well. Ask xpress spanky on bbcboards.net as he's pretty slick with the Xpress setups. My 1998 H-56 with 1998 Mariner 135 does 57 with 2 people(200 & 325 Lbs.) & around a half tank of gas(12 gls.) & a very heavy load of gear. I'm running a Turbo 14&1/4 by 25 pitch. It would actually be a little faster with a 25 Tempest Plus as my props not in the best of shape.

[BOATS]

Not sure if you ever figured it out, I have a 2012 H18SS and run a 21p three blade aluminum and bump 50mph on gps. This is at 6000 rpm on the same 4stroke 115hp you have.