First time out with this boat

[WTPhantom309]

I took my (new to me) boat out last weekend and heres what i got out of it.
1978 Vip fish/ski
1977 140 hp rude
5200 rpm wot
52 mph gps
19p alum 3 bld
trim up to 1/2 trim by the gauge would loose the bite on the prop right before that trim setting would start to porpoise or however you spell it, i could trim down abit and it would stop porpoiseing and still run about 50.Does that sound like it pretty close to running as good as it can or not?

Just thought id run it by you guys cause y'all certainly know alot more than i do. Thanks

Derek

 

[BF]

Re: First time out with this boat

Your tach sounds like it could be off to me.

I have a 17' ski boat with a 150 V6 merc, also a 19 pitch 3 blade aluminum. It'll do 52 mph (speedo not GPS) at ~5800 rpm. It can get up to 6K and a few more mph with more trim, but the ride gets a little wild.

Comparing our boats might be a bit of apples and oranges, but I can't get 52 mph with a 19 p prop at 5200 rpms.... Maybe the gearing is different between your OMC and my merc (?).

So to me the perfomance sounds about right, but the indicated WOT rpm sounds too low. (bad tach?)

If the tach is OK, 5200 at WOT seems low (over-proped).

If the tach is correct... having a 140 with a 19" prop and a 5200 WOT would mean that you'd have to be pushing a pretty heavy boat I think.

anyway, that's my $02, maybe others with this exact motor can be of more help.

 

[WTPhantom309]

Re: First time out with this boat

The heaviest thing in the boat is the batteries for the trollin motor. Its looks like a tri hull in the front and a bass boat in the back on the bottom i had about 18 gallons of fuel but the tach could very well be off, the motor doesnt sound like it lugging at all. and the hole shot aint really to shabby. Ive still got some messin to do with the weight distribution, but when i get a chance to go fishin i try to jump on it. thanks for the input. ive asked for a new tach so when i get it ill let you know what it did.

 

[kenmyfam]

Re: First time out with this boat

My scenario #1
16.5 ft Doral
140hp Johnson (1985)
14" X 19" 3 blade aluminum prop
5,500 rpm (WOT)
46 mph (GPS and speedo)

My scenario #2
16.5ft Doral
140 Johnson (1985)
14" X 17" 3 blade prop (aluminum)
6,200 RPM (WOT)
46 mph (GPS and speedo)

My scenario #3
16.5 ft Doral
140 Johnson (1985)
13.75" X 17" 3 blade prop (aluminum)
6,000 RPM (WOT)
46 mph (GPS and speedo)

Seems like my outfit gives the same speed no matter what. Could be the hull design ?
Hole shot is very similar with each set up.
Pulls a skier up (200lb) no problem with each set up.

Seems like you are doing O.K. with your set up.

 

[kenmyfam]

Re: First time out with this boat

My scenario #1
16.5 ft Doral
140hp Johnson (1985)
14" X 19" 3 blade aluminum prop
5,500 rpm (WOT)
46 mph (GPS and speedo)

My scenario #2
16.5ft Doral
140 Johnson (1985)
14" X 17" 3 blade prop (aluminum)
6,200 RPM (WOT)
46 mph (GPS and speedo)

My scenario #3
16.5 ft Doral
140 Johnson (1985)
13.75" X 17" 3 blade prop (aluminum)
6,000 RPM (WOT)
46 mph (GPS and speedo)

Seems like my outfit gives the same speed no matter what. Could be the hull design ?
Hole shot is very similar with each set up.
Pulls a skier up (200lb) no problem with each set up.

Seems like you are doing O.K. with your set up.

By the way the Doral is a closed bow runabout type and a 1985 as well.

 

[WTPhantom309]

Re: First time out with this boat

I was changing the bunk boards yesturday and noticed a few spots that needed to be glassed over and smoothed up but the rest of the hull was in good sahape , nice and smooth, my dad had a cane cutter about the same year model and hull type and he said that thatss about what it ran. I probly wont be doin much skier pullin but I really just dont wat to hurt my motor. thanks for the input guys.