Performance expectations for a smaller boat??

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,742
Considering a major down sizing for my fishing boat and would like some reassurance that I am doing the right thing.

Boat would be a mid 80's 16' Alumacraft or Lund with floor and storage.
A new tiller model 4 stroke 30 hp will be installed.
2.09 :1 ratio
5500-6300 rpm
29.8 cubic inches.

Boat, motor, gear, anchor, battery, fuel, and people should top out at 1200#.
1300# if I add an extra battery and fuel tank.

Being a very common boat size and weight, I'm hoping
to get some reliable feedback from you all.

I will be propping for a quick hole shot. Not terribly concerned with speed, but would like to have an idea on what to expect for WOT speed.
Am I right in thinking 25 + mph
 
Last edited:

cyclops222

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Mar 21, 2024
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1,419
What would be the weight of your HEAVIEST passengers in the boat at the same time? Include your weight. Must be a STANDARD 20" transom height !! Go for a very wide hull. To gain better speeds and hole shot, when loaded.
2 6 gallon tanks are foolproof to prevent ever running out of gas and needing a tow or call for gasoline.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,675
Considering a major down sizing for my fishing boat and would like some reassurance that I am doing the right thing.

Boat would be a mid 80's 16' Alumacraft or Lund with floor and storage.
A new tiller model 4 stroke 30 hp will be installed.
2.09 :1 ratio
5500-6300 rpm
29.8 cubic inches.

Boat, motor, gear, anchor, battery, fuel, and people should top out at 1200#.
1300# if I add an extra battery and fuel tank.

Being a very common boat size and weight, I'm hoping
to get some reliable feedback from you all.

I will be propping for a quick hole shot. Not terribly concerned with speed, but would like to have an idea on what to expect for WOT speed.
Am I right in thinking 25 + mph
Not 25 MPH with that load....by yourself I'd agree. Part of the equation is also the shape of the hull.....rounded chines like Alumacraft used to use or hard chine and especially a hard "reversed" chine makes a lot of difference in getting the hull up and out of the water to reduce drag and increase speed......that will help your hole shot too as would a flat transom area....no deadrise.
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,127
Gonna need to balance that weight out, I would guess about 25 mph as well under ideal conditions. Just to give you some comparison...I have a 16' Sylvan side console, wide and deep. Built-in 18 gallon tank, 4 deep cycle batteries plus other gear, the boat with gear is about 1000 lbs plus any passengers onboard. I have a two stroke Merc 4 cylinder outboard motor.
(195lbs). Top speed is 31 mph by gps, hole shot is fair, enough to pull up a skier but not impressive. At 74, my ski days are long past, so getting to my fishing spot is more important ! I would estimate your 30 hp will be barely adequate if your looking for any type performance. 1200 lbs is a lot to get moving with just 30 hp and have any top speed left over.
 

mr 88

Commander
Joined
Nov 3, 2010
Messages
2,188
60 hp 4 stroke Mercury on a 16'7" Lund XL Rebel ,side console ,not a tiller , hits a bit over 30 GPS with 2 people, full gear ,trolling motor ,two batteries and gas . .
 

mr 88

Commander
Joined
Nov 3, 2010
Messages
2,188
Gonna need to balance that weight out, I would guess about 25 mph as well under ideal conditions. Just to give you some comparison...I have a 16' Sylvan side console, wide and deep. Built-in 18 gallon tank, 4 deep cycle batteries plus other gear, the boat with gear is about 1000 lbs plus any passengers onboard. I have a two stroke Merc 4 cylinder outboard motor.
(195lbs). Top speed is 31 mph by gps, hole shot is fair, enough to pull up a skier but not impressive. At 74, my ski days are long past, so getting to my fishing spot is more important ! I would estimate your 30 hp will be barely adequate if your looking for any type performance. 1200 lbs is a lot to get moving with just 30 hp and have any top speed left over.
You mentioned everything but your actual HP .
 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,742
Here is one of them I am considering.
image.jpeg

I would keep the 35 that is on it, but I need the power tilt that comes on the new 4 stroke.
By the way, the 35 Merc 2 stroke, and the 30 hp 4 stroke, weigh the same.
70" beam
66" tramsom width
20" transom height
dead rise is almost 0 when trailer is sitting level.
Hull weight between 460# - 520# (conflicting info in brochure)
Trolling motor removed.
only 2 seats
Plan is to move battery and fuel tank forward, to just in front of the seat base on the starboard side.
I figure total weight of the rig at 850.
total combined weight of 2 passengers, 340
So gross weight loaded - 1190 , or up to 1300 if I add extra fuel and battery.

Dad had a similar model Alumacraft, but 16' 10" long, and 75# heavier.
It only had a 1987 25hp, would plane nicely with only me, was a real dog with 500# of people on board. Never had a tach on it and likely was over propped as the motor came of a 14' utility boat.

If I can cruise at 20+mph, I'll be happy.

If Not, I'll have to keep my 18'er and repower with a new 50 hp for almost double the price. Gulp.
 
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