First boat looking for some speed

[Joshua Stansbury]

THanks

Raise the motor so the cav plate is even with the top of the tunnel. It looks like you have a manual jack plate.

Then test it, again.

Thanks I'll give it a go

 

[FuzzyGrub]

Raising it will get the rpms higher, but will most likely be barely in your motors operating range. A prop with a lower pitch will most likely be needed. Test your trim positions, too.

 

[airshot]

I can tell you this, you won't get anywhere near 30 mph with a 25 hp motor. I have a 16' V bottom with a 40 hp Merc and just get 31 mph. If you get 25 mph with two people you will be doing well, very well...

 

[Axhammer]

33 CFR § 183.53 - Horsepower capacity​

According to the rule above. In the absence of a manufacturer plate stating max HP, there is a formula to guide you concerning horsepower capacity on a small boat.

For example a 16’ boat with a 72” beam at the transom, with a 20” transom, and a steering console has a factor of 96. X2 the factor, -90 gives you near 100 HP maximum.

 

[Skunked again]

33 CFR § 183.53 - Horsepower capacity​

According to the rule above. In the absence of a manufacturer plate stating max HP, there is a formula to guide you concerning horsepower capacity on a small boat.

For example a 16’ boat with a 72” beam at the transom, with a 20” transom, and a steering console has a factor of 96. X2 the factor, -90 gives you near 100 HP maximum.

Put a 100hp on it, better ad wings!!!

 

[flatheadsteve]

33 CFR § 183.53 - Horsepower capacity​

According to the rule above. In the absence of a manufacturer plate stating max HP, there is a formula to guide you concerning horsepower capacity on a small boat.

For example a 16’ boat with a 72” beam at the transom, with a 20” transom, and a steering console has a factor of 96. X2 the factor,

100hp seem a bit optimistic on a 16ft. Most console driven 18ft tins top out at 115hp. 17 footers at 75hp. My 1648 alumacraft was rated for 30hp. My 1436 polar kraft is rated for 8hp.

 

[Zum]

With that little tunnel your going to lose alittle top end speed as well...like mentioned above, 25mph.
That 13" prop is probably alittle big, especially with a load, bet an 11 or even a 10 would put you in the top end of the rpm range of your motor(where you want to be)
I have a 30hp(old 2 stroke) on a 1652(with wlittle tunnel)...a 13" prop is what I put on if Im by myself and a light load...normally use a 11ish(think 10.75"). Its been awhile since Ive gpsed but think 29mph with the 13 and 26 with the 11. The 13 is even alittle bigger then i want by myself, I like to be at the top range of rpms for my motor.
Raise her up alittle but make sure it pumps good water, I know with my tunnel I can go to high...I needa compression plate or low water pickup.

 

[Joshua Stansbury]

100hp seem a bit optimistic on a 16ft. Most console driven 18ft tins top out at 115hp. 17 footers at 75hp. My 1648 alumacraft was rated for 30hp. My 1436 polar kraft is rated for 8hp.

Yeah, I'm not putting a 100hp motor on it. I was think 40-50HP tops

 

[Joshua Stansbury]

With that little tunnel your going to lose alittle top end speed as well...like mentioned above, 25mph.
That 13" prop is probably alittle big, especially with a load, bet an 11 or even a 10 would put you in the top end of the rpm range of your motor(where you want to be)
I have a 30hp(old 2 stroke) on a 1652(with wlittle tunnel)...a 13" prop is what I put on if Im by myself and a light load...normally use a 11ish(think 10.75"). Its been awhile since Ive gpsed but think 29mph with the 13 and 26 with the 11. The 13 is even alittle bigger then i want by myself, I like to be at the top range of rpms for my motor.
Raise her up alittle but make sure it pumps good water, I know with my tunnel I can go to high...I needa compression plate or low water pickup.

Okay, I don't know it this is a typo, You said go with an 11 or 10 but here you said " but think 29mph with the 13 and 26 with the 11." which means you lose speed going with the 11" prop over the 13" was that backwards? by they way thank you for the help I'm still learning.

 

[moedelawn]

Get the motor height set correctly before you buy a new prop. You would be amazed how much drag the hydrofoil can produce when it's submerged or tucked under. I had one on a boat I bought and it was like having brakes when I trimmed down too far. I pulled it off. If you don't need it to prevent porpoising or to plane off, try running it without it. I would suspect a few mph increase in top speed.

 

[Zum]

Okay, I don't know it this is a typo, You said go with an 11 or 10 but here you said " but think 29mph with the 13 and 26 with the 11." which means you lose speed going with the 11" prop over the 13" was that backwards? by they way thank you for the help I'm still learning.

No typo...the 13 pitch doesnt work for me if I go with a load of gear or even another person...its barely good by myself
You never should lug a motor with to big a prop, always should be within the outboards rpm range at WOT.
The 11 goes slower(yes) but Im at the top of my rpm range and holeshot and planing happens real fast with the 11, plus I can load the boat heavy, without lugging the motor.

 

[Axhammer]

Yeah, I'm not putting a 100hp motor on it. I was think 40-50HP tops

The reason I posted that was to not to suggest a power level, rather to provide more info.

I find it interesting how much the HP rating can jump when a 20” transom is used, vice a 15” transom.

Adding a console is similar over a tiller steer boat.

Just stuff to think about when picking a hull for a build.

 

[LaqueRatt]

I also find the HP ratings inconsistent and curious for the reasons you just listed. What are we worried about actually? Swamping the boat? Pushing the transom in?