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View Full Version : 21 Superboat, 225 Pro Max (HELP it should do over 65 right?)



at100plus
08-13-2001, 11:24 PM
I just bought a 21 Superboat. I can't believe what it does in rough water for such a small boat. I'm really happy with the handling but I expected more speed. I pulled my 1998 225 Pro Max off my Hydrostream and rigged it on the Superboat. I was hoping to get into the 70s but found so far that I am only getting 65 at 6500 RPMs with a 24 Merc Lab Chopper. I have it setback 8" and the center of the Sportmaster bullet is even with the lowest point of the keel. This motor runs strong and pushed my Valero YT to 95.9 MPH. I know a kid who has a Superboat with a 6 year old 200 sitting right o on the transom with a stock gear case and he is getting 62 or 63 mph? What am I doing wrong? I am going to try his prop tomorrow, but besides playing with props what else can I try?

08-14-2001, 12:45 PM
There seems to be quite a bit of variation in the speeds reported on the Shadow, Superboat and Challenger hulls. This may be related to the fact that some of the Superboats are a light weight lay-up (-200 Ibs?) and others are comparing freshwater numbers with saltwater numbers. I too, would think that 225 Pro Max should push that boat over 70 MPH in freshwater. The early Challengers were solid 65 MPH boats with late 70's V6 power. Perhaps Joey Imprescia at East Coast Marine could help you out. Let us know where the sweet spot is.

Nokomis
08-14-2001, 01:50 PM
Did you use a GPS for the speed? Using the formula for projected speed, if the tach is accurate with a 10% slip you should be at 71MPH. Just for comparison, I've got a 1995 21'Checkmate w/225 ProMax that will only turn 6100 w/23 Tempest. Thats 65MPH on GPS.

at100plus
08-14-2001, 08:19 PM
I don't know what I should try first. I know that my Lab Chopper could use some thinner blades and possibly a little tweak down in the pitch category to get the RPMs up to 6750. I am running a GPS and the top speed so far is a mere 64.9 MPH. Should I really lower the engine height? does anyone concur with 2 1/2" below the pad? Is a sportmaster really a bad gearcase for this hull?

08-14-2001, 08:40 PM
With longer or heavier hulls, and sub-80mph boats, the Torquemaster is the way to go. If that Superboat is ANYTHING like a Baja or Checkmate, then you need a torquemaster and the propshaft about 2" below the bottom of the boat to start. Once you run a stock lower unit and get your best speed, if it's trimmed way out then you will need to extend the setback too. The 21 foot Checkmate Pulsare hull is around 1375 lbs, and with the heavy 3.0 225 motors with 8" of setback, they still need a lot of positive trim compared to your hot Valero YT, which needed zero trim. I'm currently in the market for a Pulsare 2100BR, and the first thing I'm going to do when I find one is make sure it has 12-14" of setback. Dream motor for my
'Mate will be a 300X, with that motor then a sportmaster should work. The 3.0 225 properly set up reaches around 75-78 mph, the extra 80? horse should put it into the mid 80's.

at100plus
08-16-2001, 07:07 AM
Yesterday I went out on Lake Hopatcong. I ran around for a while, got some seat time playing with trim, and most importantly, burned some fuel. When the boat got down to 3/4 tank, I turned it up to 68.9 MPH. I didn't change the setup at all yet. I spent the last two days grinding bolts and removing the old bunks and leaf springs and replacing everything but the frame axle and winch on the trailer. Who does the best work on Merc Choppers? I sent my SRX out to DAH last year and he did a great job with a 3-4 mph increase on my Valero. I could use a prop rework (sharper blades), a little more setback, and I will test it out with the engine lower in the water.

wetvette
08-18-2001, 10:40 PM
I have a 22 Velocity power is a pump gas 3.6 V8 375 Dyno that I run with 6" setback and prop shaft at 1/2" down it turns a 30x14.5 Spinelli 6500 with full fuel and 4 people I have no rador or GPS # yet but my other boat a 20 Advantage
runs 93 and I think the Velocity is very close to that # same Velocity with a Yamaha 225 bolted on the transom with a 23 wheel only ran 60 and needed alot of trim. there is more speed in your setup I don't think you will find it by putting your moter down anymore good luck

Jimboat
08-31-2001, 08:27 PM
What does the bottom design of this boat look like?

TTriton
08-31-2001, 09:20 PM
Is this one of the superboats that were made down here in the Keys? There really sought after boats down here.

PaulO
09-05-2001, 02:14 PM
I believe the boat that At100Plus is talking about is a 21 foot Superboat built here in Lindenhurst, Long Island. I have no knowledge of these being made anywhere but Long Island. The boat is a 1200 pound V hull of 21 degrees deadrise with 4 lifting strakes all the way to the transom and a small pad (about 6") running the last 6 feet or so. My boat (same boat) with an '82 225 Merc (fishing motor) 8 inches of setback, the propshaft 2.25 inches below the pad and running a 14.5 x 24 chopper does high 60's to low 70's GPS depending on conditions. My setup ran 67-69 with the same motor mounted on the transom, propshaft 4.5 inches below the pad and a 21 LaserII.
Similar boats with 2.4 and 2.5 performance motors run low 80s with between 10 and 12 inches of setback. Supposedly 3.0 liter mercs get you into the 80s also.
Hope this helps,
PaulO

at100plus
09-05-2001, 11:07 PM
My Superboat is from Lindenhurst on Long Island. I have a few props lined up to try this weekend. My 24 Chopper is being worked by DAH right now, and I hope to get into the mid 70s when I am done playing. My 225 Pro Max should be putting out approximately 240 hp, and I am running a sportmaster case with a hydraulic 10" setback Bob's jack. I am able to run it jacked 1/2" to an inch above the pad, and still get good water pressure. It doesn't seem to increase speed a whole lot when it is up higher, but the torque steer gets much tighter, and the exhaust gets louder. I am also going to try a CLE gearcase soon, I understand Sportmasters aren't the best for this hull.

superboat 21
09-13-2001, 09:52 PM
hey mike how are you? i have the same boat as you 21 superboat,but i have a 2.4 bridgeport on the back. i have a lot of questions ,and answers myself. maybe we can pick each others brain. are you from long island also?

Way2Fast
09-13-2001, 10:12 PM
From my prior experience with 21 Superboats/Challengers you must run the center of the prop shaft below the pad/vee to get top speed and decent handling. I would start at 1 inch below and work DOWN from there. Remember these hulls are not Allisons or Streams and should not be set up as such. Running your boat with prop shaft even with the bottom will scrub off top end speed and ruin rough water handling. Because you just went from a Stream to the Superboat, you think it handles the rough well....lower the motor and you will really see what WELL is !!

at100plus
09-15-2001, 12:47 AM
Hey Superboat21,

I would love to discuss setup.

How are you setup? Currently my best speed is 68.9 on GPS with a stock 24 Chopper. Our engines should be about the same horsepower (approximately 240). How high are you running your engine? I am getting different opinions on engine height and gearcases. I don't know who to believe. Right now I need a new stator, and my 24 Chopper is out at DAH for a rework. I am hoping to pick up a few miles per hour with the rework. I have a sportmaster gearcase, (and it is cracked at the anticavitation plate so I am looking for a CLE housing to put my gears in if that is the best housing to get, I'm not sure), and I have been running it anywhere from 1 " below to 1" above the bottom of the V and don't really see a difference in speed. When it is up higher it just has more torque steer, makes more noise, and throws more white water (like I am used to with my Hydrostream). Somehow it just doesn't feel right when the engine is down below the pad, but I do believe it is better in the rough stuff when it's down.

Some people I spoke to on the Great South Bay in Long Island last weekend told me that they are running 24 Trophy 4 blade props and they swear by them (Joe Impressia was one of them, and he was nice enough to offer to allow me to try one next time I am on the Island), One guy with 225 3 liter fishing motor said his best speed was like 71 or 72 so far and he wasn't real friendly. I was kind of surprised to find such an attitude like I was bothering him asking about his setup.

Right now I need to make some repairs, rough water boats are great, but the beating on your engine is really noticeably greater.....I don't know it's late and I'm babbling, let me know if you have any questions or answers for that matter.

Domestic Peace, and Middleastern CARPET BOMBING is in order.

Mike

superboat 21
09-18-2001, 09:26 PM
hey mike whats up? right now i have a bobs case on there,and im told that is the best one for the boat. i dont know myself. the engine is set back 6 inches,and im running it right even with the pad. that im going to change this weekend i am going to drop it 2 inches and try that then go up an inch,and see the diffrence. i also have a 24 chopper,but i would like to try somthing else. maybe if you try that trophy prop first let me know how it does. i might have to get one then.. i was told to set the boat back at least 12 inches for more speed. i would rather not do that. i love to run this boat out in the jones inlet,and try each time to push it further. it takes a pounding somtimes,but im getting real good at driving it. i love the way it takes the swells. so i would rather not push the transom with all that pounding. its in good shape for an 82 hull though. what a diffrence with the hot foot you have to get one if you dont already have it. for some reason i can only get 6500 rpms out of it then im just almost out of the water. i have to see what kind of gear ratio i have. someone told me to start there. i mean the boat will push 69 mph gps at 6500 rpm ,and this bridgeport should go at least 7000 so im missing some top end speed. i guess i will figure it out. do you have any suggestions for me to try first . i will tell you how i made out over the weekend. stay in touch jim

THE HOSER
09-19-2001, 02:28 PM
I HAVE A MOTOR FOR YOU

at100plus
09-19-2001, 03:24 PM
I currently have 10" setback, a Bob's hydraulic jack. I can only get about 1" below the pad the way it is mounted. To go any lower I have to drill new holes. I still can't believe you have to run it so low. Alot of people are telling me a stock gearcase is best at speeds under 80. Call me stubborn but that's so hard to believe too. They are trying to teach an old dog new tricks, and the dog is feeling stubborn.

I have a hotfoot, would never drive a boat without one. I too am getting 69 mph at about 6500 with my 1998 Merc Pro Max 225 and my stock 24 Merc Lab Chopper. I am waiting for my chopper to be thinned and a little bow lift by DAH. He does great work. I'll let you know how it does. He tells me he can give me significant speed increases and I don't have to be right at my rev limiter (which is 6750). He did it with my 29 SRX on my Hydrostream (gave me 5 mph with the same RPM).

send me some pics of your boat (hydrostream2.5@home.com) and I will reply with pics of mine). I go out to Long Island too. I was there the weekend of the 8th and saw alot of Superboats on the water.

superboat 21
09-19-2001, 04:17 PM
what kind of engine do you have hoser?

hoser
09-19-2001, 05:33 PM
goto the motors for sale and you will see