1983 CENTER CONSOLE 15 with 60-HP

Optimizing the performance of Boston Whaler boats
mcamuso
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Joined: Tue Jun 15, 2021 10:40 am

1983 CENTER CONSOLE 15 with 60-HP

Postby mcamuso » Sat Oct 23, 2021 10:17 am

Please give me boat speed data for a classic 15-footer with a Mercury 60-HP engine, [presumably a modern Mercury 60-HP FOURSTROKE engine].

BACKSTORY: For a 1983 CENTER CONSOLE 15 that I recently acquired, I was all set to get a F70 engine--but I want to be thorough [in my research before buying an engine].

ASIDE: a Mercury 70-HP engine is too heavy for my liking.
Last edited by mcamuso on Sat Oct 23, 2021 1:19 pm, edited 1 time in total.

altouchet@yahoo.com
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Joined: Mon Jun 26, 2017 3:15 pm

Performance of 2017 150 MONTAUK with 60-HP

Postby altouchet@yahoo.com » Sat Oct 23, 2021 11:18 am

[Moderator's note; the reply gives performance data about a completely different boat]

My 2017 I50 Montauk with Mercury 60-HP will top out at 35-MPH with one person aboard and canvas stowed. A good cruise speed is 22 to 24-MPH with engine speed between 4,200 and 4,400-RPM.

Tom in VA
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Joined: Mon Jul 12, 2021 6:04 pm

Re: Mercury 60 HP on 15’ Whaler

Postby Tom in VA » Sat Oct 23, 2021 5:54 pm

I have a 1980 15-footer. With a new Mercury 40-HP [FOURSTROKE] with standard aluminum three-bladed propeller the top boat speed is 30-MPH

I anticipate [a 1982 CENTER CONSOLE 16] with 60-HP should accelerate to 40 to 42-MPH.

jimh
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Re: 1983 CENTER CONSOLE 15 with 60-HP

Postby jimh » Sat Oct 23, 2021 7:53 pm

I had a bare bone 1976 SPORT 15. The hull weight was very light in that year--the first year of production. With a very light 50-HP (powerhead rated so really about 45-HP at propeller) two-stroke-power-cycle engine the maximum boat speed was about 34-MPH with two adults aboard.

A modern 60-HP engine will weight more (than my 50-HP engine). A 1983 hull will weigh more (than my 1976 SPORT 15). A CENTER CONSOLE will weigh more (than a SPORT model).

Using the Crouch method to analyze or predict the speed of moderate speed planing hull boats, I can deduce the weight of my 1976 SPORT 15 to be around 1,200-lbs. Adding 100-lbs for additional hull weight, 50-lbs for the center console model, and 100-lbs for more engine, gives a boat weight of 1,450-lbs. With that weight an 60-HP the predicted speed will be 36.6-MPH.

As you can see, weight has a significant influence on boat speed, particularly on small and light boats. If your CENTER CONSOLE 15 with 60-HP engine weighed only 1,200-lbs, it would probably reach 40-MPH.

On the basis of the Crouch analysis, I would expect your 1983 CENTER CONSOLE 15 powered by a modern 60-HP engine to reach a top speed of about 37-MPH.

Why not get the F70 engine you mentioned as your initial choice?

mcamuso
Posts: 21
Joined: Tue Jun 15, 2021 10:40 am

Re: 1983 CENTER CONSOLE 15 with 60-HP

Postby mcamuso » Sat Oct 23, 2021 10:19 pm

jimh wrote:Why not get the F70 engine you mentioned as your initial choice?
I spent the summer on a boat with two new Mercury engines. I was very impressed with the engines. With engine shortages the way they are, I figured having a second option to the F70 in both price and availability wouldn’t hurt.

dtmackey
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Joined: Thu Sep 28, 2017 9:29 pm

Re: 1983 CENTER CONSOLE 15 with 60-HP

Postby dtmackey » Tue Oct 26, 2021 9:18 am

Jim is right on the money with the top speed. The classic 15 hull in a center console model is very different that the 150 Montauk, so that comparison is apples to oranges and not relevent for the question asked.

The 15 center console is a boat great balance and everything seems to be placed just right for performance. With a 70 Yamaha 2 stroke it'll run 42-43mph if propped correcly and very similar with the F70. With an F70 and jackplate you will see over 45mph, propped correctly. The Yamaha F70 is a great motor and ideal on a 15" Whaler.

The Merc is also a good motor, but doesn't have the reputation of the Yamaha, nor have they sold as many, so you may be able to get one sooner than the Yamaha.

This summer I sold a used Yamaha 70 2 stroke to a gentleman that purchased a brancd new Merc 60 for his 15' Whaler. When he told me this, I asked why and his response was eye opening and hopefully not representative of all Merc 60s.

He was running his Whaler and the motor went into limp mode, so back to the dealer it went and it was a bad sensor in the EFI system. He went back out another time and had another concern, which was resolved by the dealer quickly. The last straw for him was another time his lower unit failed, gear through the side of the lower unit (he showed me the pic). Back to the dealer it went and he was told that lower units were on backorder and they couldn't get him back on the water this year (that was late July). He was working with the dealer for them to buy back the motor and decided to purchase a tried and true early 1990s Yamaha 2 stroke 70hp from me to put on his boat so he could finish out his season and walk away from the Merc since his confidence level was low. It's also interesting to note that the Mercury is built in Suzhou China.

D-

R DAVIS
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Re: 1983 CENTER CONSOLE 15 with 60-HP

Postby R DAVIS » Tue Oct 26, 2021 12:35 pm

I have a 1983 Sport 15 with a 2019 60 HP Tohatsu 4 stroke and 14" pitch, 3 blade propeller, and a hydraulic jack plate with 6" setback. With a fairly heavy load it will run top end of 36 MPH (GPS). That motor weighs 216 lbs. which is quite light for a 4 stroke. It has a very good hole shot for a 4 stroke, which is important to me when taking off in very shallow grass flats in south Texas bays, without damaging the seagrass. The boat does not chine walk, even with the jack plate in the full up position, but it feels as if it probably would, if driven much faster.