1988 SUPER SPORT 15 Re-power; Five Questions

Optimizing the performance of Boston Whaler boats
gmcdonough
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1988 SUPER SPORT 15 Re-power; Five Questions

Postby gmcdonough » Mon Sep 17, 2018 11:44 am

I recently purchased a 15 foot Super Sport with a 1988 60-HP Mariner and I would like to re-power.

Q1: Can I use a long shaft or is a short shaft preferred?

Q2: Is a 40 hp adequate?

Q3: Should I go with a 50 or 60 hp?

Q4: Is the 40 hp adequate? (I do not need a rocket ship). I would like to be able to take my grandchildren water skiing. ages 8-13.

Other uses will be primarily taking two couples and some small kids from Jamestown RI to Newport RI on harbor cruises.

Q5: Should I go with a two-stroke Evinrude or a four-stroke Suzuki?

I look forward to your input

Thank you very much

Jerry McDonough

jimh
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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby jimh » Mon Sep 17, 2018 12:36 pm

gmcdonough wrote:Q1: Can I use a long shaft or is a short shaft preferred?

A1: for advice on the proper engine shaft length, see the specifications for the SUPER SPORT 15. You can find the specifications for the SUPER SPORT 15 in two places:

  • in the REFERENCE section article on the 15-foot hull
  • in the REFERENCE section article on all hulls 9 to 31 feet

The REFERENCE section is found at

http://continuouswave.com/whaler/reference/

The article on the 15-foot hull is found at

http://continuouswave.com/whaler/reference/15/

The article on the specifications of all hulls 9 to 31-feet is found at

http://continuouswave.com/whaler/refere ... tions.html

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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby jimh » Mon Sep 17, 2018 12:40 pm

gmcdonough wrote:Q2: Is a 40-HP adequate?


A2: For the minimum power to get the classic 15-foot hull on plane, see the specifications mentioned above in my reply A1.

Since the boat presently has a 60-HP engine, reducing the power to two-thirds of what you have now is going to cause a significant reduction in performance. In order to judge if you will find 40-HP to be adequate for your use, you should assess if a reduction in power to 40-HP from 60-HP and the accompanying loss of speed, acceleration, and load-carrying will still meet your needs.

gmcdonough wrote:Q3: Or should I go to 50 or 60-HP?


A3: If you re-power the boat with 60-HP the performance will be similar to what you have now, although perhaps affected by a weight increase of a new engine compared to the old engine. If you re-power with 50-HP the performance will be somewhat less. Only you can judge the needs and compare to the present performance.

Many people use between 50 and 70-HP on a classic 15-foot hull.

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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby jimh » Mon Sep 17, 2018 12:44 pm

gmcdonough wrote:Q4: Is a 40 hp adequate?


See A2 above.

When four adults are aboard a classic 15-foot hull, if the adults are perhaps 200-lbs each then 800-lbs is added to the total boat weight. On small, light, open skiff boats like a SUPER SPORT 15, adding 800-lbs to a boat hull that weighs perhaps 600-lbs represents a very significant increase in the total boat weight. This is going to be a significant reduction in performance with four adults compared to one adult.

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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby jimh » Mon Sep 17, 2018 12:44 pm

gmcdonough wrote:Q5: Should I go with a two-stroke Evinrude or a four-stroke Suzuki?


All modern outboard engines are generally very nice products. My general advice about what brand outboard engine to purchase is to choose a dealer that you like, who has a long history with the brand, who offers factory-trained service and support for the brand, and who has experience in selling the brand as a re-power engine, not just a dealer that sells new boats with that brand already installed.

Other considerations for engine choice include:
  • weight; too much transom weight is a problem on small, light, open skiffs like a SUPER SPORT 15
  • required service and ease of winterization; performing oil changes for four-stroke-power-cycle engines can be a burden; a modern two-stroke engine does not have a lubricating oil sump; an E-TEC engine has a great self-winterizing procedure if you are boating in an area with winter storage necessary
  • re-use of existing controls, wiring, gauges, and propeller can affect choice for re-power brand;
  • general preference of the buyer for a particular technology; two-stroke-power-cycle engines generally deliver strong performance compared to equivalent displacement four-stroke-power-cycle engines, unless those four-stroke engines have some performance enhancing technology
  • the costs; some brands are sold primarily on the basis that their cost is lower.

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dg22
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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby dg22 » Mon Sep 17, 2018 3:30 pm

With the Evinrude E-TEC engine there is only 8-lbs difference between the 40-HP (232 lbs) and the 60-HP (240 lbs). I would go with the 60-HP E-TEC; it would be a lot better for pulling the grandchildren water skiing. Also, it would be better for re-sale.

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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby jimh » Mon Sep 17, 2018 8:18 pm

For some background on the performance of the classic 15-foot hull, read several reports at

Owner Testamonials
http://continuouswave.com/whaler/reference/15/testimonials.html

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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby jimh » Tue Sep 18, 2018 10:30 am

dg22 wrote:With the Evinrude E-TEC engine there is only 8-lbs difference between the 40-HP (232 lbs) and the 60-HP (240 lbs)


This is not quite true. The 40-HP and 60-HP engines weigh the same, 240-lbs, when both are configured for remote steering and controls. The two engines have the same power head and gear case. The difference in horsepower rating is the principal difference between them, not their weight.

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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby jimh » Tue Sep 18, 2018 10:31 am

For reports from other owners on the performance of a SUPER SPORT 15, read the more than 200 articles found with this link, a search of the forum archives:

LINK to SEARCH RESULTS

dtmackey
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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby dtmackey » Tue Sep 18, 2018 10:03 pm

For your needs, I'd lean toward a 60-HP motor that weighs no more than 250-lbs. I'd even consider the Yamaha F70 four-stroke-power-cycle engine--great engine. Water skiing with grandkids to me implies:
    --you, the driver
    --another adult for spotting, some states stipulate only an adult can legally spot
    --one grandkid being towed on skis
    --one or more additional grandkids in the boat

Anything less that 60-HP and I think you will be disappointed, especially as the kids grow and a smaller engine will struggle more every year pulling the kids up on skis as they grow each year.

You are correct that you may not need a rocket ship, but for a skier to get popped out of the water by a boat with adequate power is more pleasant than to get dragged through the water as a boat struggles to get on plane.

D-

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Dutchman
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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby Dutchman » Wed Sep 19, 2018 10:11 am

I second dtmackey's reply above. You should keep in mind that an E-TEC two-stroke-power-cycle engine will have better torque at the low end than a four-stroke-power-cycle engine, resulting in quicker acceleration and a water skier popping-out on top of the water instead of dragging behind the boat.

I recommend the 60-HP and the manufacturer that gives the best dealer service in your area.
EJO
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50th edition 2008 Montauk 150, w/60HP Mercury Bigfoot

El Rollo
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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby El Rollo » Wed Sep 19, 2018 2:02 pm

I agree 100% with all of the opinions above.

Just to offer you a comparison, I too own a 1988 Boston Whaler 15 powered by a Yamaha F70. My boat has some additional weigh, (trolling motor and 3 small AGM batteries. Last summer we took the kids to the Colorado River and pulled them on tow-behind toys and waterskis. Wth me and my wife in the boat pulling up a 14-year-old boy on two skis, the 70-HP worked great. However, I wouldn't want any less, especially now that he has grown so much in the last year.

Also keep in mind that pulling up a skier on a single ski will have considerably more drag than on two skis.

I think the Evinrude E-TEC 60 would be a good choice. As mentioned above the two-stroke-power-cycle engine should have better low-RPM torque.

Mr T
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Re: 1988 SUPER SPORT 15 Re-power; Five Questions

Postby Mr T » Fri Oct 19, 2018 8:29 pm

I own a 1982 SPORT 15 that came with a 1982 Mercury 50-HP four-cylinder two-stroke engine. The performance was very much in agreement with what has been reported on this site. Recently i was able to change to a 1990 Mercury 60-HP three-cylinder two-stroke engine, and I have been very happy with the result. I am running this as a fishing boat with two Group-24 batteries and a trolling motor in the bow. With just myself and a full 15-gallon fuel tank the boat can get to 40.1-MPH with a very stable ride.

A 60-HP engine is the minimum amount you would want to have.