Max HP rating 1979 vs 2017

[FormerParatrooper]

I was looking at the current MirroCraft Boats website and noticed something. My boat the F-4604 circa 1979 has the data plate stating it has a 25hp max rating. The F-4604 this year states it has a 15hp max rating.


The differences I found between both models:

2017 1979
Beam 58" 57"
Bow Depth 27" 25"
Bottom Thickness .051 .060
Length 14' 1" 14'

Both weigh 175#, max capacity of 835#.


Is this difference based on the average weight of motors then and now, or is it due to 2 strokes motors vs 4 stroke motors? Is there a logic behind the change of HP ratings?

 

[Sinkingfast]

I would, if forced at gunpoint, guess a little more cya safety factor and added weight of a 4 stroke at this time. Maybe weaker transom?

Since no gun point, I will not comment...

 

[lckstckn2smknbrls]

In the early 80's the way HP out put was rated changed. It had been rated at the powerhead then changed to at the prop.

 

[Charger25]

Might just be me , but it seems that a lot of newer boats have a much lower HP ratings

 

[FormerParatrooper]

In the early 80's the way HP out put was rated changed. It had been rated at the powerhead then changed to at the prop.

So would that affect the overall performance? Would a 25hp in the 70's perform about the same as a 15hp now?