Top Speed Question/Discussion

[whipper]

This sorta keeps me up at night. The XB2003 and XS 2003 ill use as an example what puzzles me. What causes you guys that are running 104-107 mph with a 260,280, S3000 to top out below 110 as an example? A 280 with 260 electronics on a GS or XB with a good 30 pitch should be capable of 110-112 at 8000 rpm. What im interested in is it the gearcase blowing out or the hulls top speed with that power to the floor maxed or just the comfort zone is getting freaky feeling? The reason for the question is that most of you guys like Todd,Jeff and chad for instance are running 27 or 28 pitch props to achieve 105 give or take. Shook runs a 29 to get over 120 with his S3000 on his 02. Does the {frontal} area of the 03,s need more power to push it past 110? What would happen if you put a 30 or 32 pitch on with a stout 280 with some revs built in and tryed to get 8000 to 8500 rpm? would they still top out at 106 and change?

Ive often wondered what the limiting factor was with those speeds that seem to be the most common top speeds. You hear of the odd 225,s doing 101 or 102 with a 30 or 32 pitch prop so i just wonder why a 260 or 280 cant get more than 4 mph more with the same prop? i dont want this to be a pissing match Im trying to see if its just straight power stopping the hull, the risk of blow out becomes to great, or the feeling isn't right like to flighty for instance since ive never been there. When Brian had my GS he went 104 with his 280 on her also. What would it take to make these 03,s go faster?

 

[K.Kiser]

My disclaimer of ignorance is I've never owned a GS.. With that said I think its the downforce created by the deck of boat progressively trying to push the boat back down harder and harder as the mph increases.. Eventually it requires too much prop bite to hold up that amount of downward pressure, which is a lot of robbed power that could've otherwise been used to push forward parallel with the water.. All in the same effect, the boat is increasingly nearing a blowout.. If that's incorrect, I'll add it to my file folder

 

[whipper]

The same effect for the XB03 That seems to be around the same speed. The larger windscreen on the XS and XB perhaps or this force may come from the hulls deeper bow than the others that are faster like the SS,XB02,RR,XR? they all are little narrower and not quite as deep. Less of a hole to punch? So even useing a taller prop the top speeds would be fairly similer as thats were the forces become to great for the HP. Flat deck or Molded. Good answer kiser.

 

[RedAllison]

Those hulls simply have a wall! They are punching a considerably larger "hole in the wind" than any of the smaller hulls. I think in the GSs case that is truly best exemplified by Todd Bucknell's old GS. That thing would run 102-103 with 3 people, a cooler, full of wet towels & a "days worth of crap" all in it. Yet when he emptied it it would only gain another couple mph. That just shows that "wall" & hulls limit. (Also shows he & Mr. Thom pretty much had the setup PERFECTED in "the family truckster"!) Same goes for the XB03 as well, that big console becomes a spoiler in the low-mid 00s & really starts pushing the bow down! Jerry Jaco told me years ago that he didn't care how much power you put on the tail of an XB, he said that hull just WOULDNT run over 110-113! I've never seen an "honest 110 XB" but I know based on the XBs I've driven over 100 that I WOULDNT WANT TO run one that fast!!!

I drove Todds GS several times over 100 over the years & it "felt different" than the XBs for sure but IMHO the GSs "difference felt" is more a perspective/look/view ordeal because when looking over that flatter, lower deck of the GS you don't get the feeling that it's responding to trim nearly as much as you do in an XB. Obviously it IS lifting but you just don't "see it" as much. When you tick the trim on a XB "you KNOW it!" BOTH however require more trim than the smaller hulls & that's where I think that combines with the "larger hole" & that "wall" to produce a feeling that's just not as locked in & on rails like the smaller boats. (The battleship sized 21s REALLY require your attention as the needle climbs past 85, I simply can't imagine what they feel like at 100+ & nor do I want to!)

An XR01 is a "1 hand on the wheel, Sunday cruise" @ 105-110, how far you wanna go & how much gas you got? Lou's SS/260ss was the same way at 99.xx (the bottom of it was done by Glenn Reynolds).

 

[Dave Hensley]

Red what XB's are you referring to? Not an expert but have a bit of seat time in the Xb2002, XB2003, XR2002, XTB21 and XR2001. The fishing boats were built, and have pencil rolls for fishing motors. 100 mph is a watershed for pad configuration, prop, gearcase, weight distribution and driving talent. I don't care what you say 100 mph in an Allison starts to seperate the men from the manginas. Both XR's are just a an exercise in willpower and horsepower. They will get the job done. The XTB 21 is as cool as it gets for a sidesteer boat. I have ran 96 in one and felt like I was at the wall, took the trolling motor and windshield off and ran 99 and wanted more prop and HP. Learned something that day. The XB2003 is SUPER SENSITIVE to that console. Put a windshield on top and you just went 2x on sensitivity. The trim it takes to overcome the aero downforce of that console starts to be a tug of war on the bite the prop has.get her up flying at 101-102 and need more trim to keep the nose up, the 800 pound gorilla is standing right on the dash, you will find outhow fast the boat can turn. Combinations and balance. Yeah some will say I did this and I did that in a particular boat but if they go 10 mph over what normal folks can do they have spent big bucks and hours upon hours testing. My hat is off to Shook. I know he has ran over 120 many times in his 2002. That was his focus. He had a combination. Bolt his motor and prop on another boat and results would differ. I have been 113 in a 2002 that was on rails and the limiting factor was a big gearcase. I have went 102 in a 2002 with XR6 and got hurt,twice.

 

[XXXR2001]

Aerodynamics and hydrodynamics......there is a point of diminishing return.

 

[whipper]

Thats great information guys for sure thanks!! I really like what you were saying Red about Todd with a load and without. Thats says allot right there about were the Diminishing return point is regardless of hp. When the Hydrodynamics reach that {wall} its going to take a unproportionate percentage of hp to gain a little speed at that point it seems. Then there's the, do ya really want to go there with those two hulls also.

 

[propmanjay]

The difference between 90 and 100 is big. For me 100 to 110 was real big and worse as the speed went up! In the SS my azz would start to pucker at 104 and above. I always felt like the SS was being pushed down when on the pencil roll "unmolested lip" . Seems like the GS would be the same way x2.

 

[whipper]

Anyone ever run without the lip at speed in these hulls and was there any difference? I know Ive heard years ago some guys did but dont remember who and what speeds. All as I can remember was someone saying that in an 03 they run better over 100. But thats probably debatable? Pretty sure the GS and XB03 were designed to run 100 - 103. The lip, pad, fulcrum everything was made not to reach much higher. Some do but not really indented for those speeds like the other hulls are is what I gathered. As always to run the fastest with the least amount of HP.

 

[patches]

Whipper, you need an XR2001

 

[2fast4mom]

Everything said thus far is true. I learned to drive an Allison on an XB2003 and the side steer and the weight of the boat (first with a 225 promax, then a 280) plus that console "air dam" were definitely limiting factors. Since then, I've owned or own many different models. Amongst the current five is a 1995 GSE with a 200XS SS (2006 motor) which will do top end of 85-87 routinely despite load. However, one day and one day only my son brought her back with a 94.3 on the gps--light load and a tailwind, so that number is definitely an outlier.

The XB2003/280SS I could get high 90's routinely, but the fastest she ever went was 101 and change. No matter what prop, or setup change there simply wasn't any more there. Mine was a 1998 and I swear it was heavier than any other xb2003 I've driven. Felt like it had a lead layup coat. But the limiting factor on these boats (XB2003) in my experience is that console, followed by hull design/frontal area.

Years ago, I posted a thread on "what's the fastest anyone has had an xb2003?" The winner at that time was Myron who reported a high end of 107. Now on that boat, that's really hanging it out there. Personally I'd never want nor have any desire to run an xb2003 that fast. IMHO that's a 100mph hull before the spook factor shows up and over 101, side steer, you can see the angel of death or at least his cousin angel of hook in the backseat from the rear view. Having said that, the hull is sluggish enough to give you a slow motion warning (compared to an XR or SS) that makes a reaction possible. Everything happens a bit slower in both the XB2003 and XS2003 in terms of the hull saying, "I'm looking for a place to spit you out" whereas the XR2001 and especially the SS says "I'm looki....(WHAmO!)

My current XS2003 GSE with the 200XS has become a favorite go-to boat because of several factors. The 200xs SS is so quiet and so good on fuel economy, you'd think the gas gauge is busted. It has a Stainless marine gauges for both trim and hydraulic jack plate height, which have marks telling me where they are at all the time. It has a wide angle ski-type rear view mirror so I can see the height of its rooster tail and I sometimes use this to gauge whether or not she would like more trim; rule of thumb so I've heard is that you are losing bite, lift, and efficiency when the heighth of the rooster tail exceeds the top of the cowling on top end. She definite gives you plenty of warning and even repeats herself as she gracefully announces "I'm fixin to do something stupid!" Whilst beginning to feel as if on ball bearings and starting a starboard lean. Sometimes I'll throw my left leg over more to port and lean left with rest of me and she will get over it. I've never (knock on wood) swapped ends with this boat. It's just too forgiving, and announces her intention so clearly that anyone with experience will see like a flashing neon sign.

I think I'll add a side-slide seat to the GSE. That might gain me a mph or two on top when solo.

It currently has a Detwiler hydraulic jack plate with 11.25" of setback. Great unit it is. The steering on this boat is also hydraulic, my only Allison to have it, and though it makes for an easy drive I'm just a dinosaur and prefer the ride guide because of the tactile feedback and mostly the steering wheel rocker trim switches.

Personally I'd never have turn signal trims on an XR or SS. Simply for me, not enough cushion in reaction time. These hulls do EVERYTHING faster, and you gotta keep your attention wired tight. My personal best is 117mph on an XR2001 / 300 drag turning a 24 Yamaha at Lord knows what rpm, prop worked by Jeff Calbaugh and this prop is or was owned by Bryan Welch.

Todd Bucknell's XS2003 to me was a benchmark for what this model is capable of. Will never forget the sight that fully loade "bThtub) fully out of the water at 106 with a load of victims ..um ..passengers in her. That setup was DIALED.

Lastly, I have found, running a stock sport master, that my highest top end numbers on the GSE are always with the gear case set LOWER in the water, NOT higher. She loves like 3/4" to 1" below the pad. You can watch the gps lose mph as you raise up the height from there, regardless of prop. I think it's because of the subwoofer and amp up in the bow.

Sorry for the long post. Was just in the mood....Be safe.

Lou

 

[Dave Hensley]

One note on the XB2003. I sold one to Kurt Ristow that had been back to Allison for a "blueprint" on the pad. I don't know how much was done to the pad, very little apparent difference, but that boat with two up and a 260 would show you 101mph everyday and literally drove itself. It was having some fuel delivery issues the only time I drove it but it was so different from all the other XB2003's I had driven there was no comparison. I think it had 4-5 more mph in it. Most of the others were a test of willpower to finally get enough trim in the boat to go fast. None were too bad on landing though. One other thought on the bottom work. I like fishing out of the 2003. Would be nice to have one with center aisle, dual Fast Bass consoles, long front deck and driver and passenger seats about where the bench is. The XB2002's vary across the board on stability at speed. Most of mine have been white knucklers above 100mph. I owned one, a 1987, that was owned by Darris' brother in law and spent many hours upside down at the factory. It also had a lower unit that was a 4 hole CLE that Darris built a nose cone for and was the prototype for the Sportmaster. Ride/Guide steering and it had almost no torque at 100+. best Allison by far that I ever drove. Always wished I had kept that one. Had a 1997 Mariner Drag and was a beast. So, Whipper, at the end of the day with a sample of two massaged pads by an expert, I am throwing out there that you can change the entire personality of the boat by working on about a 3"x 11" area. Who does the work determines if the personality is Jekyl or Hyde. I had a "Hyde" bottom job on a 1994 XB2002 done by Lou's favorite engine builder....GPI....what a dog. No pencil roll...easy to drive but terrible angle of attack at the bow. Oran St. Marie bought it and it went straight to Allison. Put the lip back on it and from what I hear it is a rocket.

 

[propmanjay]

What Eric said!

 

[SLOmofo]

Whipper, water is hard. I was very stupid and I am very lucky. That said. With no lip, the unequal console and to much HP, I stay away from triple digits as much as I can. If I live 11 more days I'll be 65.

 

[RedAllison]

Red what XB's are you referring to? Not an expert but have a bit of seat time in the Xb2002, XB2003, XR2002, XTB21 and XR2001. The fishing boats were built, and have pencil rolls for fishing motors. 100 mph is a watershed for pad configuration, prop, gearcase, weight distribution and driving talent. I don't care what you say 100 mph in an Allison starts to seperate the men from the manginas. Both XR's are just a an exercise in willpower and horsepower. They will get the job done. The XTB 21 is as cool as it gets for a sidesteer boat. I have ran 96 in one and felt like I was at the wall, took the trolling motor and windshield off and ran 99 and wanted more prop and HP. Learned something that day. The XB2003 is SUPER SENSITIVE to that console. Put a windshield on top and you just went 2x on sensitivity. The trim it takes to overcome the aero downforce of that console starts to be a tug of war on the bite the prop has.get her up flying at 101-102 and need more trim to keep the nose up, the 800 pound gorilla is standing right on the dash, you will find outhow fast the boat can turn. Combinations and balance. Yeah some will say I did this and I did that in a particular boat but if they go 10 mph over what normal folks can do they have spent big bucks and hours upon hours testing. My hat is off to Shook. I know he has ran over 120 many times in his 2002. That was his focus. He had a combination. Bolt his motor and prop on another boat and results would differ. I have been 113 in a 2002 that was on rails and the limiting factor was a big gearcase. I have went 102 in a 2002 with XR6 and got hurt,twice.

Sorry for the delay Dave, yes I was referring to the XB03! You are EXACTLY correct with the 800# gorilla on the dash reference. My XB03/225ss (JC worked Sporty) was NEVER empty, I never removed the troller nor batts, & it likewise usually had my customary 15 rods & enough tackle to merit my own tackle section aboard. When going for 93+ runs loaded like such + 2 people aboard, the trim was LAID ON (& prayed on!) The lip was stock & the windshield was never removed either.

 

[Dave Hensley]

Exactly Red! Absolutely had to lay on the trim with the Xb03. They seem to just labor getting cleaned up and then POW they jump up on the pad and drive like an A BOAT. i always like to hear/feel the water contact with the hull move from right under the driver back past the livewell. No trim gauge needed!

 

[flying07]

Great post and info in this thread, thanks guys!

 

[patches]

Dave, is the 94 that Oran bought from you the yellow/white one he's still running. That is easily the lightest XB2002 I've ever seen

 

[Dave Hensley]

Dave, is the 94 that Oran bought from you the yellow/white one he's still running. That is easily the lightest XB2002 I've ever seen

Yep. I have one here that is about 20 pounds lighter and it has a livewell!! The Chigger Sisco boat was around 635lbs. I have heard. I didnt weigh Orans but guessing 685-690 with seat, steering, jackplate and tank??

 

[h2oskiier30]

Exactly Red! Absolutely had to lay on the trim with the Xb03. They seem to just labor getting cleaned up and then POW they jump up on the pad and drive like an A BOAT. i always like to hear/feel the water contact with the hull move from right under the driver back past the livewell. No trim gauge needed!

I was ready to sell my XB03 a month after I bought it due to this. I had heard the horrors of too much trim on A-boats so much, I was scared to let 'er fly. I finally rode with a buddy who already had an XB03, and figured out I was too scared of the trim. I got behind the wheel, got up on the trim, and fell in love. Still to this day, there's nothing like the feeling when an Ally jumps up on the pad and takes a set. That was, and still is, the best driving XB03 I've ever driven.