how fast should my boat go???????

scon

Seaman Apprentice
Joined
Aug 29, 2010
Messages
42
Re: hull speed?

Re: hull speed?

the racing is on concrete...lol not in a boat........guess i should be more clear sorry
 

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: hull speed?

Re: hull speed?

Do some reading over in the I/O section regarding horsepower additions. MOst will say don't waste any money on a 5.0, but that mods to a 5.7 might be worth a little. Read up on Reversion which is sucking water into the intake due to valve overlap and severely limits cam choices and hence limits typical street mods you may be used to.

In your case you need to focus on proper trim, weight balance, and then dialing in the correct prop. This assumes that the engine is running properly.

FWIW, we try to keep this section free of engine stuff. Very difficult as proper oepration (trim, balance etc.) does belong here. So the way I see it is: General discussion, here. Resulting focused discussions on the prop, prop section. Resulting focused discussions on the engine, I/O section etc. Good luck!
 

starcraft1982

Petty Officer 1st Class
Joined
Feb 7, 2010
Messages
277
Re: how fast should my boat go???????

Challenger84,what do you recommend for WOT?And remember,its an inboard not an outboard!
 

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: how fast should my boat go???????

OK guys. I merged these two threads as we are all posting the same kind of info, to the same poster, about the same issue . . . how fast should I go.

There were no 305's (5.0s) in 1996, but there were two in 1995. Very common to have an engine that is a year older model than the boat.

The 5.0 was rated 190 bhp at the propshaft and had a 1.65 gear ratio. The 5.0LX was rated 205 at the prop and had a 1.5 ratio. Both were 4200 - 4600 recommended WOT RPM.

Oh, and I deleted a couple of posts to try and make a little more sense out of the merge.
 

rwidman

Lieutenant
Joined
May 27, 2004
Messages
1,396
Re: hull speed?

Re: hull speed?

someone told me today that my hull cant exceed a certain speed is this true and how do i find out what that speed is?

I hope that from reading the posts, you have figured out that this applies to "displacement" type boats. That is, boats that don't climb partially out of the water when run fast. A cargo ship would be a displacement hull. My boat (in the photo) is a "semi displacement" boat. Most of the boats you see running around on lakes and rivers are "planing" boats. The other end of the spectrum would by a hydroplane racing boat that is almost completely out of the water at top speed.

Either the person you talked to doesn't know what he/she is talking about, or one of you misunderstood the other.

As for getting more speed from a boat or getting more power from an engine, these questions get asked all the time and the bottom line ie - If you want a faster boat, buy a faster boat. There is no magic pill to make a boat faster or an engine more powerfull.

Tune the engine up to specs, make sure you have the correct prop that gets you to wide open throttle (WOT), make sure the hull is clean and free from marine growth, and reduce weight in the boat. If you're on a river, you can go faster with the current than against it. Same goes for wind.
 

tawood

Petty Officer 2nd Class
Joined
May 19, 2009
Messages
128
Re: hull speed?

Re: hull speed?

rpm is 3800-4000 @wot not sure on gps...how acurate is gps?

Depends on how many satelites you are receiving, and a few other variables, but usually gps is accurate to greater than .2 mph (thats more accurate than two tenths of a mph).
 

SeanT

Senior Chief Petty Officer
Joined
Jul 8, 2009
Messages
661
Re: how fast should my boat go???????

Powering a displacement hull past it's hull speed will push the bow through the standing wave and create another standing wave.
__________________
...and this creates an aquatic boom, right? :D
 
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