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Author Topic:   13 Sport performance upgrade
jrthiele posted 11-12-2003 09:23 AM ET (US)   Profile for jrthiele   Send Email to jrthiele  
I've got a 2000 13' Sport with the 25hp Bigfoot 4-stroke motor. It's always been marginal on power but at the time I bought the boat nothing larger was offered with the 4-stroke. My problem is just getting the boat to plane with 3 or 4 people aboard. I use it as a crabbing boat and tender so top speed is not important, but it is a problem when I can't even get it to plane with a moderate load on board. I keep the boat in saltwater constantly so I applied an epoxy bottom paint called copperpoxy. It works great but it is not as smooth as the orginal gelcoat. I doubt that the rough finish is helping my performance but it would appear that 25 hp is just not enough power for a boat of this weight.

I'm considering several options for improvement and I would be interested in any advice:

1. Add engine mounted lift wings such as the Sting Ray or Hydrofoil.

2. Add Nauticus Smart Tabs, the self adjusting trim tabs.

3. Lower the prop pitch to improve acceleration (but I'm not sure what is available or what pitch would be better).

4. Swap the motor for a used 30hp bigfoot motor from my local dealer. They indicate that the 30 hp is a three cylinder motor with more power and torque. This would not cost much but 5 hp hardly seems worth the trouble.

5. Swap the motor for a 40 hp bigfoot. This appears to be unrealistically expensive. At this point I think I'd be better off just buying a new boat.

Jarhead posted 11-12-2003 06:20 PM ET (US)     Profile for Jarhead  Send Email to Jarhead     
I have the same setup. As I fish alone getting on plane is no problem but staying on plane at lower RPM is [falls off around 4200 RPM].

I plan on installing a Doil-Fin to help with the problem. I know it'll work because I installed one on an old 13' Whaler with an old 25HP Johnson years ago. Worked great.

BTW, it also jumped up on plane from the get go. It's also the cheapest fix on your list.

Good luck...

kglinz posted 11-12-2003 06:39 PM ET (US)     Profile for kglinz  Send Email to kglinz     
I don't have a 13 Sport and I hope a 13 owner responds to your post, however I do have Copperpoxy on my boat. My coating was applied with a airless spray gun and is rough as well. I lost about 2 knots off top end, but I don't think that is your problem. My 2000 Whaler catalog indicates 25 HP is the minimum recommended HP on your boat. You're looking at a max load spec of 935 lbs. Of that, at least 250lbs is motor, battery, and misc equip. That leaves 685lbs for passengers and other equipment. 4 passengers must be a max load. I would think you need max power with that heavy a passenger load. I'm not sure why you would have a "Bigfoot" motor. They designed for Pontoon boats and are geared lower than normal motors. Have you checked max RPM with a light load. I am a believer in 4 Strokes, but a 2 stroke 40 HP could be a better choice on your boat.

Would you be Jim Thiele, of American Blimp, by any chance.

Kemp Lindsey / Boise,ID

Jarhead posted 11-12-2003 08:45 PM ET (US)     Profile for Jarhead  Send Email to Jarhead     
Hey kglinz... A 13 owner DID respond to his post.

kglinz posted 11-12-2003 09:21 PM ET (US)     Profile for kglinz  Send Email to kglinz     
Sorry. I type pretty slow and spent a lot of time checking spelling and referencing the Mercury website. When I started you hadn't responded.
jrthiele posted 11-12-2003 09:36 PM ET (US)     Profile for jrthiele  Send Email to jrthiele     
Yes, I am Jim Thiele with American Blimp. Besides boats on the water, I mess around with ships in the air too.
BMR posted 11-13-2003 04:16 AM ET (US)     Profile for BMR    
You should try shifting weight forward. You would be suprised on the affect of moving the battery under the consoe. On small boats, it does not take much to move the CG and improve planning. However, if you go too far the boat will not trim as well. On these small boats it is also importiant to distribute the persons weight evenly throught the boat. For example, if the boat has trouble getting on plan with 2 big guys on the aft bench set, then move one to the forward seat and the boat should come up better.

Jarhead posted 11-13-2003 06:23 AM ET (US)     Profile for Jarhead  Send Email to Jarhead     
I talked to another 130 25HP Big Foot owner and asked about problems he had with getting up on plane. His comments were similar to yours. No problem with a normal load and 2 adults but 3 or more was just to much weight for the 25.

A bigger boat may be your best option?

Good luck...

kglinz. Can't tell you how many times thats happened to me. :)

skred posted 11-13-2003 08:58 AM ET (US)     Profile for skred  Send Email to skred     
I owned a 1989 13 Sport. The hull weight was approx 330 lbs. Your hull weighs over 600, if I recall. My Yamaha 30 would do anything I asked of it, including pull adult skiers with 2 passengers and average fuel, etc. load. I don't think the Bigfoot 25 has enough oomph to do the job for you. It really needs the 40 hp...
kglinz posted 11-13-2003 10:26 AM ET (US)     Profile for kglinz  Send Email to kglinz     
You have an E mail at your profile address
Bigshot posted 11-13-2003 01:25 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
4 adults in a 13 is hard work no matter what engine. I love 13's but 4 people is too much. Heck 4 people in my Montauk is tough.
Moe posted 11-13-2003 02:22 PM ET (US)     Profile for Moe  Send Email to Moe     
I'll just say that with 750 lbs of people, gas, and gear, mostly loaded toward the stern, our 150 Sport has no problem planing, or staying on plane at 3200 rpm on flat water or 3400 rpm in 2-4 feet of chop, with the 60HP BigFoot EFI. There's 66" of helm thwart seat width for 3 hefty adults, and 33" of removable seat width next to the console.


poker13 posted 11-13-2003 07:16 PM ET (US)     Profile for poker13    
I once drove a sport 130 with a 25hp and it sure was slow--once it actually planed, that is. I was sitting at the helm with the guy who was showing me the boat sitting to my left on the thwart seat (I figure I was over 220 lbs. at the time and this guy must have been close to 200) and his son (a little skinny kid who couldn't have been more than 5 years old) at the front thwart seat. The boat simply wouldn't plane! The fellow told the kid to sit on the bow locker, and that's when it finally planed. We couldn't have been going faster than 25 mph at WOT. I was definitely not impressed. :-(
CHRISWEIGHT posted 11-15-2003 02:37 PM ET (US)     Profile for CHRISWEIGHT  Send Email to CHRISWEIGHT     
I think you will find that most 13' boats powered by a 25hp will run at or slightly above 25mph, try a doel fin. If that doesnt work throw the fat one into the drink.

had a 13 foot bonwitco with 25hp Mariner, two adults 440lbs and a 180lb adult on a ring no problem. so I think you will get there but you will have to experiment with loading and planing aids.


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