Top speed comparisons

[a70eliminator]

Mainly interested in the 60's V-4
My 67MFG is by far a speed demon even with the 80HP engine, is it because of the hull design being almost a flat bottom at the transom?
What are some of you guys's top speeds? 32MPH here and seems like @ 4700 it should be faster but I can't identify the prop either, my old 60hp did well with a 10 x 9-1/4. What size prop should this 80HP have in general for my 16' wastfield?

 

[pduquette]

Re: Top speed comparisons

I'm no Merc guru ( I got a '73 9.8 ) :redface: So take this FWIW . I think that your motor should be run with a higher rpm redline . I know you have been working on your mounting setup , so I'd try a couple of props next .


As for my setup , I'm using a 2 cyl . j50 (1980) on my 14'-10" Oxford with a 12-3/4' x 17p alu prop. got 30mph@4800rpm last year . picked up a 13" x 15p 4blade Comprop.......yet to be tested

 

[*EdC*]

Re: Top speed comparisons

If it's any help, I run a 13 1/4 x 19 on my 80 Merc. Rpms for my set up are around 5500 @WOT

 

[Mark_VTfisherman]

Re: Top speed comparisons

Mainly interested in the 60's V-4
My 67MFG is by far a speed demon even with the 80HP engine, is it because of the hull design being almost a flat bottom at the transom?
What are some of you guys's top speeds? 32MPH here and seems like @ 4700 it should be faster but I can't identify the prop either, my old 60hp did well with a 10 x 9-1/4. What size prop should this 80HP have in general for my 16' wastfield?

I am no propping expert but I would think that 32mph is great in your boat
A different prop might bump you up a few mph though- don't know the engine so don't know the RPM.

Your post got me thinking and I decided to share my thoughts. I know that my '64 Niagara (14') is basically the same hull shape but a lot smaller. My best has been a little above 33mph on a GPS WOT with my 1985 40hp Suzuki. With the old '64 Johnson 26-ish mph was tops. So your Westfield - a much bigger boat - with a '67 80hp seems fine to me at ~32mph. The HP of the newer engines is measured at the prop, while the sixties' were rated at the powerhead. If your boat had the same percentage speed improvement if you installed a new 80hp to replace your sixties motor, you might get up to about 37mph

 

[Original Mark 30]

Re: Top speed comparisons

1971 Fishin' Caprice: (via GPS)

Mercury 1500, standard 4-blade Aluminum: 43mph @ low revs (5200ish)
Mercury 1500XS, DAH 3-blade stainless: 54mph @ roughly 6000 rpm
Mercury "175" V6 2stroke with DAH 3-blade stainless "chopper" : 65.4mph (6400rpm)

Not bad for a "Noah's Ark" of a hull design." : )

 

[pduquette]

Re: Top speed comparisons

T'aint no sled ......that's a sliegh ride!!! WOOOOO HOOOOOOOO!!!!!! peter