Speed?

Hey guys! I just got back from my first trip to the lake with my new boat/engine. That engine ran PERFECT but I do have question though. The boat is a 21' Omega (open bow, semi-v hull.) The engine is a 454 with approx. 475 hp (I didn't have it dynoed, so I don't know exactly.) The pump is a fresh (at least that is what I was told) Jacuzzi WJ (mixed flow.) I don't know yet what size impeller it has. The boat turned 5000 rpm at 52 mph on a GPS. This was with about 20 gallons of gas and two people in the boat. Is this a resonable speed for a boat this size, or should I start looking for something that might be wrong? Several people at the lake felt that the GPS was wrong but I seriously doubt it because it is brand new. I just don't think that anyone was very happy with the results they got. Most of the people still felt that there boats were at least 10 mph faster than what the readings they would get. I guess it just feels faster on the water. Anyway, sorry to ramble on, does anyone have an opinion on my question? Thanks!

I've been there and done that. The truth hurts, and there is a very good chance that the GPS is correct. 52 mph sounds a little bit slow, but a 21 foot Omega is a pretty heavy boat as well. If you aren't absolutely sure about the condition of your jet drive, you may be giving away a lot of speed. Also, if you let the engine spin a little bit higher, you'll probably get to where the horsepower peak of the engine is. That means a smaller impeller and a blueprinted drive. Of course, the hull condition and straightness plays a big role also.
Just for a quick comparison, my CP Gullwing has run a best of 82.6 mph on GPS with a roughly 475 horse 454 at 5200 rpm.
SteveM.

I agree,it's too slow for 5000RPM with a new pump.Sorry ,the GPS is usually 1/10th of a mile accurate,so either your engine is low on power or your boat got overweight.A 21 Omega is a heavy boat but with the afformentioned power and RPM ,you should be close to 60MPH.Check the bottom of your boat,and check your floor for water absorbtion.You can easily be a few hundred pounds overweight.

Thanks for the info. I checked the bottom of the boat and found that it has more hook than a tackle box. I don't know if I'll ever undertake a project like getting rid of it though. I don't know if it would be worth the hassle for what I am using the boat for. I'm definetly going to go through the pump this winter though. Is there any way to check to se if the floor is waterlogged without tearing out the carpet? I hate to tear it out if I don't have to since it's pretty new. Thanks again for the info!!

You can be fairly certain that the GPS is not far off. How certain are you of the accuracy of your tach? Found the tach in my Taylor to be off by 1000 rpm (too high).
Just my .02
Bill

If you have soft spots in the floor, it's waterlogged. If so, check with rotdoctor.com, he may have some suggestions to get you a little more life out of it before having to replace the whole floor like I'm doing.
Slick