Performance expectations for a smaller boat??

[roscoe]

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

 

[cyclops222]

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]

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]

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]

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]

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]

Here is one of them I am considering.


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.

 

[cyclops222]

Size will ALWAYS win in approaching bad weather !! Especially if you MUST run into it. All the way home / dock. Been there many times. Keep the bigger boat and motor !!

 

[Texasmark]

Round chine, deflection rails along the chine tells you that it rides in the water and the rails are to deflect the spray coming up. A lot of stuff in that boat. If you just want 20 you probably will make it. Looks like it has been well cared for and not a lot of usage. We both know what that means......a lot!

 

[airshot]

You mentioned everything but your actual HP .

Sorry about that...40 hp

 

[airshot]

35 hp two stroke will outperform a 30hp four stroke by a noticeable amount!
If you want the same performance as the 35 hp two stroke, you will need at least a 40 hp four stroke.

 

[mr 88]

Why don't you take it for a sea trial, that'll tell you all you need to know.

 

[Alumarine]

A friend has a 16 ft Lund SSV utility boat.
3 bench seats, nothing else.
boat=345 lbs, 2 guys=300 lbs, 15 lb anchor and 3 gallons of fuel.
With a 25hp Honda we get 25 mph.

 

[cyclops222]

I have friends that weigh 250 #. We jump up and down to get on plane ?

 

[nola mike]

My CS is about 1k # with me on it. Upper 20's easy, 25 hp 2 stroke merc. It's now waterlogged (probably 300# in the hull...) and compression is down to 100# on both cylinders. Still 26-7 mph with just me.