Comanche3Six

How could he know?

Comanche3Six

I have the original sea trial given to me by Val Jenkins when I picked up the boat at the factory. It says boat + fuel 4996 lbs, gross weight 5481 lbs.
It now has a heavier engine, merlin block and heads + supercharger. Also a #3 speedmaster with hydraulic steering. I tried to post a copy of the document but I am having difficulty.

MitchStellin

I read where every 100lbs will cost 1 mile per gallon so it has to take speed, I notice it with 4 big guys but not until top end. Fuel makes a huge difference, I always use 7 per gal also.

Steve 1

Nothing is free it takes energy to move weight.

44MTI

Troutly'
I didn't follow your math. I got 194 -32=162 Divided by 32=5 mph. But again this assumes your are running a cat that is subject to weight. My fountain ran just as fast full maybe faster in the rough, 105-108 on gps
Jamie
Randy told me that my 42 with 900's 6's weighs about 10500lbs dry. But that was just off memory and the boat is 2001.

MitchStellin

The person who said "the best things in life are free" obviously never owned a boat or had his priorities screwed up because boating is the best thing in life but it is a long way from free.

BROWNIE

Square root of gross weight in pounds divided by horsepower x speed in stature mph = "k". Then add the weight and do it again. God it's early for this.

dreamboater

Assuming I am doing this right, I am coming up with a difference of 1.5 for "K", I am assuming that is = to 1.5mph lost when the weight was added. If I did this right than on a 4000lb boat running 107mph, 200lbs would equal approx 1.5 mph. Anyone else try this?

Chris288

Nothing scientific here but this is my understanding...... for every additional 8-10 lbs it takes an additional 1 hp... Most boats take anywhere from 15-20 hp to go an extra 1 mph... so based on these numbers, approx 150 - 200 lbs = a 1 mph loss... Makes sense, If I have a full tank of gas ( 700 lbs ) or a 1/4 tank ( 200 lbs ) I loose approx 2 mph.. Of course there are many other factors that effect this but for the most part, I would say this is a good rule of thumb..

dreamboater

Well, when I went back and checked that it was only a difference of .3 mph. That doesnt seem right.