1977 18sf vs 2003 20sc
 

Has anyone owned a potter built 18sf (I have a 77) and then bought a 20sc manufactured in the 2000's? I'm just curious of the ride differences ..... I'm thinking about an upgrade. The 20sc has a 4stroke yami and it's got my wheels spinning. I also like the bow space for family and fishing. Storage sucks on the sc though! Thanks

I had a 76 18 and an 05 20. Hard to make a comparison giving two different set ups. The 18 had a 140 no tabs, the 20 had 200 hpdi and tabs, the tabs alone made it ride like a bigger boat in a chop, and it was quick. I would suggest taking a ride in the 20 on a windy day and then you can decide.

I agree, the key to a soft ride is good balance. Trim tabs can help compensate for a stern heavy situation, but they'll add drag, increase fuel burn and reduce speed. I've ridden in the 18 Snookerd had with a 130 hp 2-stroke that rode very well and I don't believe it had trim tabs.

The key metric to test would be the min planing speed on both rigs w/o using trim tabs. All of Moesly's designs (the 21, 19 Bowrider, 20cc and Seafari, 27 Seamaster and 25 Seafari) with original power (~300 lb motors on the OB models) seem to plane at about 12 mph, but min planing speed will increase as motor weight increases. I would bet that an 18 with light 2-stroke power will ride better than a 20 with a ~500 lb 4-stroke on the transom. I speak from experience because my boat rode better with a 300 lb motor on the transom than it did with a 430 lb motor shifted 30" aft on a 150 lb bracket. Min planing speed went from 12 mph to 22-23 mph! By adding trim tabs, a Doelfin and a stern lifting 4B prop, I got it back down to 12 mph but at some penalty in speed and fuel burn.

And if you want more storage, take a look at a 20' Seafari or Sceptre!

Ok...I'll be more broad. how Does the 20 ride overall with a 4stroke 150?

Thanks Bushwacker

Those motors are at least another 50-60 lbs heavier than my E-TEC (be sure to compare WET weights, with full filter & 6-8 qts of oil in the crankcase!). If it's hanging on the transom with a 3B prop and no fin, I'd guess it would perform about like mine did originally before I added that stuff, i.e. min planing speed in the low-mid 20's. If motor is on a bracket and they didn't move the console/batteries/gas tank forward to rebalance (an option I didn't have in the Seafari), I suspect it'd be worse.

One clue as to how well it's balanced is how deep the chines are immersed at the transom at rest. First 2 pics below show how mine sat with 300 lb motor with full and empty gas tank. With an empty tank, transom chine was maybe 1" deep, with trim tabs almost at surface, and maybe 2" deep with a full tank (Pic 1 & 3) . In last pic with bracket and new motor, chine is 4.5-5" deep. (35 gallons). The 2" bootstripe is in same location in all pics, just repainted w/new motor. Remember that the Hermco bracket has a lot more flotation than the typical Armstrong bracket, so it probably offsets most of the motor weight. I suspect waterline would be similar if motor was hanging on transom. The big CG shift doesn't show up till you get on plane and flotation tank is out of the water!

Thanks bushwacker
It doesn't have a bracket. It has trim tabs though with a 2006 Yamaha 4stroke. Looks like that outboard is 500 pds with oil.

I plan on sea trialing her this week. I'm very interested to see the ride variances. Emotionally I will have a hard time letting the 18 go but I'm head over heals for a 4 stroke. We use our boats every weekend during summer. Thanks again

Before you launch it, look to see where the waterline is on the transom and if it has a fin and 4B prop. If not, figure you'll need to add them!

During the sea trial, pull the tabs up and pay close attention to how slow it will run and stay on plane as you throttle back, as that will tell you if they shifted gear around to offset the weight of that heavy motor! Then try it again with the tabs down to see how much they help. Don't know what sort of seas you're used to running in, but the 20' hull is relatively light and will start to go airborne in 3' seas at around 20 kts, so being able to hang on plane at 12-15 mph is a big deal if you plan to run offshore very much!

A properly set up 18 will ride just a liiittle bit better and be a liiittle bit drier than a properly set up 20. You'll regret getting rid of the 18 just like everyone else thats had one...

It is a myth to me if that's the case. Dry hull weight on 18 is 1400 pds. Dry hull weight on 20 1600. Beam is one inch different. 2 feet should make the boat ride better. I guess I'll find out soon. Will let you know.

Either way light is right. Unless you enjoy training porpoise.

Sandy, wouldn't a 20 ride a lot like an 18 with a 2' hull extension?
"Flipper, Flipper - the King of the Sea!

Light is right?

Looking to redo an 18' as well. I am thinking the new Suzuki 90 is the ticket. 365lbs or so I believe. With battery under console hoping it will be "light is right" and will self bail and not need tabs.

Denny- I totally agree.....just because people can put a 500 lb motor on a 20 doesn't mean they should. That crowd that doesn't pay attention to the value of the CG is overlooking one of Carl's major ingredients to the great ride.

My 2 18's with v4 2 strokes had no tabs and were beasts offshore!

Light weight engine. PM inbound about your boat.

I understand light engines on potter built boats are imperative, I own an 18sf with a 2stroke 150hp. It runs great but it will always be an 18 foot boat. I have a family of 4. Correct me if I'm wrong but aren't the (2000's) 20sc WITHOUT COFFIN BOX made to take a larger more modern engine and still built on the exact 20 mold? It's a different cut out and transome height. Thanks

Bud, get the launch.
Lassie, what is Flipper trying to say to us?

Layup here...

It's a Formula!

People want a 150-200 on their 20's and 4 strokes are what are on the boats....try both a light 20 with under 430 lbs of motor then a 20 with 500 lbs of motor. Most guys who know the difference will agree with a light motor. DF 140 / E-Tec 150-200 2 stroke is the most power vs acceptable weight IMHO.

Snookerd's had experience on the 18's with a 2 stroke V-4 and V-6 and a 140 Zuke 4S, plus he had a 23 with TWIN 225's on it, so he's experienced the impact of motor weight on a boats ride and handling more than most folks. His 18 with the V-4 rode surprisingly well with 2 adults, 3 kids and a 65 lb dog!

Regarding the 20's, the Potter and SeaCraft Industry boats were actually 19'8" LOA with 20" transoms. The later Tracker models were actually a bit longer (maybe 20'6"?), had 25" transoms, and are probably a bit heavier since I believe they used the cheaper, heavier and less durable plywood to core the deck instead of balsa core. For that reason it may handle a heavy motor marginally better than the older models, but the difference would be small. A neighbor of mine had a late model 20 with a 150 2S on it; I think it may have had the coffin box on it, but his main complaint was lack of storage.

It you're looking for an extremely versatile family boat with much more usable room than a CC model, check out the really nice Seafari that was advertised on here just a couple weeks ago with a brand new 115 E-TEC on it. The E-TEC's are efficient, smooth, quiet, and smokeless just like the 4 strokes, but with much less weight and maintenance, and more mid-range punch where you need it for getting on plane!

My `89 Slacker is 20'4". 25 " transom. The deck design was raised sometime in the 80`s.
No coffin box.

Anyone know the year?

I can walk my skinny ass in the corner and water comes in. 96 150 rude at 365 lbs.
Even with that light motah on her transom, she porpoised when I got her. New prop design and raising the pig solved that. No tabs. Batts under console and console moved forward 2 "s

My 20 is rated for 235 hp per cg plate. That brings you over 60 and chine walking lessons commence. Even with huge 12 x 24 tabs. Ask Bones.

Why do you think you need that much powah? Bushwhhhackah sees 50 light with his e tec 150.
JUMPS outtah the hole.

Minimum plane speed is the most under rated performance parameter evah.

If you are planning on four or more very often, you might want to consider a 23.
Three on my 20 just gives me a human trim tab.

CG is your focus. You can embrace it.

A local neck who is unknown to CSC put a straight shaft 351 in a 20. Pocket drive. A sea snail passed him on plane out the cut.

Somehow marketing has us all believing max hp and weight have no bearing.
Cheers,
GFS

That twin 225 set-up was insane! That boat looked cool, but was worthless with 900 lb of motors, 30 ' setback no flotation bracket, and another 5 inches with a CMC jack plate. I learned my lesson!

She looked like a Sixties A F/X gasser at 60 ft. down the track whilst sitting on the hook.

My thoughts are rarely aligned with yours...???
You are not alone.

I bought the 20sc. I can admit that they do not ride alike at all. However, I wouldn't say that the 18 rides better. In fact, the 20 rides more on top of the water. The 18 rides deeper and heavier to me. The weight of the engine causes no harm to that boat. It does have a fin & turned 5800 rpm at 48mph. Glad I did it

Furthermore after spending more time on the boat. I had heard it all wrong. The fit and finish on this 2003 is exellent. It seems to be built actually very well. hardware is nice and still looks clean. Deck and cap are nice and strong. It handles a 150 4 stroke with zero issues. I'd do it over 10 times. TKS for all the advise.

Glad to hear you're happy. A friend has a 2004 20 that's held up very well and seems built pretty well.