PDA

View Full Version : Finding the best X-dimension



2112
10-18-2008, 06:46 PM
Jim and others...

How do you determine the best X dimension? Obviously, most of us are pretty much stuck with the factory height but some of us have a little room to play.

Tres told me my Gladiator would be a much better boat if I added spacers to the shorty Sportmasters. He did not elaborate at to how much or what improvements can be had.

I can tell you I am not really disappointed in the boats performance. One thing that is different from my previous boats though is this boat does not like too much trim. It slows top top end and cruising speeds noticeably if I trim her out too much. She actually prefers just a slight trim up from the lower shafts parallel to the bottom.

My logic would say the factory nailed it but Tres' comment has stuck with me and now I have a venue to discuss it in detail.

MOBILEMERCMAN
10-18-2008, 07:56 PM
My guess is the factory nailed it as far as top speed is concerned. I am sure Tres has ridden in many Gladiators with different set ups and has expressed his personal preference. To add spacers it may lose a little bit on top, but carry better and be more responsive at cruise speed. What is more important relative to how you use the boat. Is it the last mile an hour or the quality of cruise.

Knowing from your posts I've read use should ask him specifically what size and try it.

2112
10-19-2008, 02:32 AM
He was very concerned about the rear getting away from me in a turn. I make sure to slow down and keep trimmed out when turning. So far it turns great.

But I am not saying that was the reason. About the only compromise is getting on plane but I am willing to stay propped like the way I am and have that one issue.

I tried a Steve Baker 5 blade P5 x prop and that did loosen up the tail a bit. The 4 blade Bravo 1s stay hooked up a little better.

Offshoredrillin
10-19-2008, 07:50 AM
Phil seems to like the 4 blade bravos on his as well, unless it is 6's, Tres has been very vocal in the setups of glads, and imo it was one of the main reasons that he saw a need for his school. my assumption would be that his suggestion was to make the boat handle better whilst turning.

back to x set up, is there a formula for locating it? while a boat is unrigged, where would you want the tip of the bullet? If I was to ever switch my tiger to 6's from xr's, what would I start with for calculating it?

Ratickle
10-19-2008, 10:11 AM
I am also very curious. On the BT it was switched from Bravo's to 3A's and the previous owner said it was the hardest boat to drive he ever owned. Said he needed three hands to keep it on the water. We are changing some things on the bottom water intakes and exhaust, but what about the x-dim and center of gravity changing from the trans add and additional 3A weight? It was changed at Dollar.

2112
10-19-2008, 12:57 PM
Another observation;

My previous boats, with lower X-dimenisons, ran faster the more I trimmed them out. I had to find a balance between speed and getting the ride too scary. On my non-stepped bottom Warlock, I had to use the trailer switch to get the drive up where I wanted it.

As I said above, this boat will start slowing down when I do that. I can't get the bow up any further. It also rides level and isn't scary. So I am not complaining.

This is leading me to the "last Gladiator" and the NXTs. Are those surface piercing? I assumed so with #6 style props. I am anxious to hear how it runs with those drives.

MOBILEMERCMAN
10-19-2008, 01:30 PM
2112,
The way you have described the trim in your first post tells me it is set up right. It should go fastest with trim near level. Thus pushing straight ahead. Since you are not leveraging the bow up it doesn't get out of shape when encountering swells. When a boat goes faster trimmed to the max it says the drive is too low.

MOBILEMERCMAN
10-19-2008, 01:42 PM
OSdriling,
Why would you change from 6's?

Offshoredrillin
10-19-2008, 02:14 PM
OSdriling,
Why would you change from 6's?
to 6's from xr's


When a boat goes faster trimmed to the max it says the drive is too low.

this makes sense as well, when running with my xrs I can get them up about 6/7 and no tab and the boat flys(best of 76 with half tanks and 2 people, straight bottom Tiger). however, my boat is heavy and with shorties, it would probably be a nightmare to plane, so for 500's and xr's I'm good where i am, but if I wanted to bolt on whipples, i would overpower the drives, hence my questions for setting up 6's :)

2112
10-19-2008, 07:37 PM
Rob,

Just wait till the X-Drive arrives:sifone:

Did you see the 5" stand off box for ITS (I assume you have that with the XR's) that Diamond Marine had in the new products section of OSO?

I wondered if I had an application for that. Don't want to spend 10K and then just find out it was a bust.

Offshoredrillin
10-19-2008, 09:25 PM
Rob,

Just wait till the X-Drive arrives:sifone:

Did you see the 5" stand off box for ITS (I assume you have that with the XR's) that Diamond Marine had in the new products section of OSO?

I wondered if I had an application for that. Don't want to spend 10K and then just find out it was a bust.
actually my boat is a 2000, no ITS then. I do have ITS going on my 20 with a blackhawk. I'm not sure if the ITS would help or hurt on the tiger, for every 12" of set back you need an inch higher of x dim, thats why the imco boxes go up at an angle. My concern with the pkg i have now, if i did put ITS on, would the props be too far back and make the boat bow heavy?

Griff
10-20-2008, 11:59 PM
2112, I can tell you that when added 1" more spacer to the Pantera, it carried the bow better and the propslip went down. It was a noticeable difference. The prop hooked up better, cruise speed was 2-4mph better and I picked up 1-2mph on the top end. The X was set pretty high from the factory.

Geronimo36
10-21-2008, 10:32 AM
Jimmy, I could use some help with X Dimension....

I can't get a definitive answer and my assumption is they never really figured it out.... I'm at 14"... One person tells me I should be at 14 7/8", the other tells me 15 1/2"..... One says run 3 blades the other says 4 blades...

Boat runs mid 80's, both people say it should be running 90 or low 90's....

Frank

MOBILEMERCMAN
10-21-2008, 10:50 AM
Frank, I don't know what is ideal for you boat. As you have seen opinions will vary. Maybe because of power, props , and/or personal preferences. I suggest drawing info from previously rigged boats, pay attention to proposed speed and er on the side of too high. It is much easier to lower than to re rig and raise. Once it is rigged all you can do is try different sets

As far as the basics go does it run fastest with it trimmed way out or trim slightly positive? Do you like the way it handles? Have you already tried different types of props?
How much effort and money are you willing to spend? Will it be more fun?

If your boat stays on a lift I would make sure the bunks are supported and extend an inch or so past transom. I see many boats with 6,12 or 18 inches hanging over the back of the lift. This will in time reduce your speed.

2112
10-21-2008, 11:37 AM
Are everyones spacers made by the same company?

Griff, that is more like what Tres was referring to. It has been a couple years since the course. Is your bottom stepped? Did you start out with Shortys?

Thanks

Tres
10-21-2008, 06:23 PM
OK it goes like this. The steps create several layers of disturbed water. If the hull is light, comes in under weight, you can run a higher X because of less disturbance.Many boats from factories are run with no interior and very little gas. Once the owner has a normal set up of fuel, people and all his personal junk, the boat weighs more, there is now a larger deep High and low PSI disturbance that is covered in more layers requiring the prop to grab more dirty layers of water creating more slip. The amount to lower is up to testing but I have too many boats that I just throw a spacer in and WHALA! the speed increases and the handling improves.Go figure. OLD NEWS rise the drive to go faster, good for conventional bottoms but lower your drive on Step hulls to get clean water that is useable. Putting money into props after heights are factored is key.

MOBILEMERCMAN
10-21-2008, 06:35 PM
Tres,
Welcome and thanks for sharing.

Long time no see. Will you be visiting Key West for races?

Offshoredrillin
10-21-2008, 06:55 PM
OK it goes like this. The steps create several layers of disturbed water. If the hull is light, comes in under weight, you can run a higher X because of less disturbance.Many boats from factories are run with no interior and very little gas. Once the owner has a normal set up of fuel, people and all his personal junk, the boat weighs more, there is now a larger deep High and low PSI disturbance that is covered in more layers requiring the prop to grab more dirty layers of water creating more slip. The amount to lower is up to testing but I have too many boats that I just throw a spacer in and WHALA! the speed increases and the handling improves.Go figure. OLD NEWS rise the drive to go faster, good for conventional bottoms but lower your drive on Step hulls to get clean water that is useable. Putting money into props after heights are factored is key.
great info and thanks, my tiger is a 2000 straight hull, 500 efi's(worked to 615 hp and 670 tq) xrs top speed of 76. what could I expect if I was to put ITS on it, or besides breaking drives, adding whipples?

2112
10-21-2008, 07:20 PM
Tres, Thanks for coming down and filing us in. Since you know the Gladiator so well, where should I start on spacer size and whose should I get?

Geronimo36
10-21-2008, 07:41 PM
Frank, I don't know what is ideal for you boat. As you have seen opinions will vary. Maybe because of power, props , and/or personal preferences. I suggest drawing info from previously rigged boats, pay attention to proposed speed and er on the side of too high. It is much easier to lower than to re rig and raise. Once it is rigged all you can do is try different sets

As far as the basics go does it run fastest with it trimmed way out or trim slightly positive? Do you like the way it handles? Have you already tried different types of props?
How much effort and money are you willing to spend? Will it be more fun?

If your boat stays on a lift I would make sure the bunks are supported and extend an inch or so past transom. I see many boats with 6,12 or 18 inches hanging over the back of the lift. This will in time reduce your speed.


I hear ya Jimmy and that's what has me going nutz.... time and money are two things that are lacking these days.. As you already know I can do just about everything on my own. I have a hard time swallowing the cost of $7K for shorties when i know what the parts costs list and my own labor to put them together. Also, I just assume de-rig the boat and put in a new transom and go from there but the time factor doesn't exist... If I could find a cheap set of shorties or even a set of shorties to test with, rather than buying them, it would be a great starting point. An there in lies the problem, finding a 2" shortie with a BMax vertical shaft....:ack2:

I've got the power and the boat handles great, better than most, I just know I'm leaving 5-7 mph on the table. Last year I pinged a bunch of 36' owners and asked them to measure their X Dimensions with little luck...there's not many of us out there.

I spoke with Bobby and with Eric about it and they both agree I'm too deep but they both have two different measurements.... Every 36' was built and tested at Lake X but they custom built the boats depending on what power the owners put in them.

Geronimo36
10-21-2008, 07:46 PM
OK it goes like this. The steps create several layers of disturbed water. If the hull is light, comes in under weight, you can run a higher X because of less disturbance.Many boats from factories are run with no interior and very little gas. Once the owner has a normal set up of fuel, people and all his personal junk, the boat weighs more, there is now a larger deep High and low PSI disturbance that is covered in more layers requiring the prop to grab more dirty layers of water creating more slip. The amount to lower is up to testing but I have too many boats that I just throw a spacer in and WHALA! the speed increases and the handling improves.Go figure. OLD NEWS rise the drive to go faster, good for conventional bottoms but lower your drive on Step hulls to get clean water that is useable. Putting money into props after heights are factored is key.


Tres, what kind of X Dimension data do you have on the 36' Apaches?

Tres
10-22-2008, 07:59 AM
Tres, Thanks for coming down and filing us in. Since you know the Gladiator so well, where should I start on spacer size and whose should I get?Shoitie? or XR standard. Inco has what you need. In the Glad I would try a .5 spacer.Call me if you run into trouble

Tres
10-22-2008, 08:03 AM
Tres, what kind of X Dimension data do you have on the 36' Apaches?I dont keep all my data. Raising the drive on conventional is good but with the aid of a 12 inch set back is the best compliment. Stellings has kit that will help you with results.the box jogs up one inch. you will wind up raising the engine too. Starting and ending with 3 inch up from old location.

Geronimo36
10-22-2008, 03:21 PM
I think I'm going to keep it the same unless I find some shorties in a fire sale.... The boat runs great, it's just giving up mph, and I don't have the time/resources/patience to mess around with it right now.. :(

2112
10-22-2008, 03:33 PM
Shoitie? or XR standard. Inco has what you need. In the Glad I would try a .5 spacer.Call me if you run into trouble


ITS with 2" shortys Running with 4 Blade Bravos and 5 BLade P5 X's massaged by Steve Baker (works props for the hering crew at races).

Griff
10-23-2008, 03:12 AM
Are everyones spacers made by the same company?

Griff, that is more like what Tres was referring to. It has been a couple years since the course. Is your bottom stepped? Did you start out with Shortys?

Thanks

No, that was on my 28 Pantera single engine. They run pretty flat and thats why the rough water ride is so good on them. It had a notched transom which they don't do much on pleasure versions. Because of the notch, they have to raise the X quite a bit to clear it and they always use spacers. The X was way high from the factory and the boat left the factory with a 2" spacer. The propshaft was still only about 3.25" below the bottom. I talked with Jo at Pantera quite a bit about it and he agreed that the drive should go deeper to help the boat lift the bow some more.

Griff
10-23-2008, 03:20 AM
2112, I would try some 1/2" and 1". I would try and borrow some first or buy used. 1" should be plenty. There is not really anything that can go wrong with them. Its just the spacer, coupler and longer studs. Mine was an IMCO. Not sure if anybody else actually makes them. I think they might just be repackaged under different brands.

Tres
10-23-2008, 07:51 AM
Seeing that this glad is near normal I want start .5 I dont this 1 inch will work as well, but you never know. The TG would be the boat to suffer more weight forward or more weight from just loading where a 1 inch might be more exceptable' Just remember that after the spacer change a prop change may also be in order.

2112
10-23-2008, 10:25 PM
Tres.

I did add about 400 lbs with the full length Stelliings, Ford engines and overkill closed cooling. Also when I am boating in Puget sound, where there is no 91 octane on the water, I tend to boat with pretty full tanks most of the time.

Griff, I was wondering who made them IMCO or Latham?

MOBILEMERCMAN
10-23-2008, 11:21 PM
Here is IMCO spacer page

http://www.imcomarine.com/pages/sterndrives.html#drive%20spacers

I will make a call to see if there is a set available to test.

Tomas Wallin
10-24-2008, 04:14 AM
No, that was on my 28 Pantera single engine. They run pretty flat and thats why the rough water ride is so good on them. It had a notched transom which they don't do much on pleasure versions. Because of the notch, they have to raise the X quite a bit to clear it and they always use spacers. The X was way high from the factory and the boat left the factory with a 2" spacer. The propshaft was still only about 3.25" below the bottom. I talked with Jo at Pantera quite a bit about it and he agreed that the drive should go deeper to help the boat lift the bow some more.

Hey Griff,

Do you remember what slip you had with the prop shaft 3.25" below the bottom (and what HP, prop, nosecone or not and speed) since I have pretty much exactly the same dimension and I have been having large slip numbers with mercury labbed Bravos but I got 11% with an out of the box 28 Bravo at 89mph.

Do you have a cabin, I cant remember?

Geronimo36
10-24-2008, 08:21 AM
Griff, Have you tried the Maximus prop with your X Dimension?

Tres, do the Maximus only work good on a step bottom boat? How about a conventional V with a high X?

Griff
10-24-2008, 03:40 PM
Griff, Have you tried the Maximus prop with your X Dimension?

Tres, do the Maximus only work good on a step bottom boat? How about a conventional V with a high X?


That boat belongs to Dude Sweet now. I think he tried one after upping the HP. The 5 blades had just come out and were'nt avalable in a small enough pitch until shortly before I sold the boat.

Griff
10-24-2008, 03:48 PM
Hey Griff,

Do you remember what slip you had with the prop shaft 3.25" below the bottom (and what HP, prop, nosecone or not and speed) since I have pretty much exactly the same dimension and I have been having large slip numbers with mercury labbed Bravos but I got 11% with an out of the box 28 Bravo at 89mph.

Do you have a cabin, I cant remember?


The slip was over 20% with a stock 26 Bravo prop. HP was about 540-550. I had a full cabin. Slip dropped to 16-17% by going down another inch.

The full cabin is what was really keeping the bow down for me. Normally only the race/no cabin boats have the notch, but the person who had it built wanted the notch.

I think 11% is about the best slip you're going to get.

Tomas Wallin
10-27-2008, 10:21 AM
The slip was over 20% with a stock 26 Bravo prop. HP was about 540-550. I had a full cabin. Slip dropped to 16-17% by going down another inch.

The full cabin is what was really keeping the bow down for me. Normally only the race/no cabin boats have the notch, but the person who had it built wanted the notch.

I think 11% is about the best slip you're going to get.

I went for a 62mile trip on saturday with the labbed 31 Bravo. I carefully started going into boost so at 5000rpms I had 2-3PSI and 75mph with 23% slip. At 5100 I had 5-6psi and 80mph with 20% slip.

I have 2-3psi left and 700 rpms so it looks promising that the prop will be pretty good with a minor tweaking. The mid range suck with 30-20% but I can live with that if it's fast as hell at wot...:sifone:

I will try having someone to videocam the next ride so I have some more inputs to work with during the winter.

Griff
10-27-2008, 01:42 PM
I went for a 62mile trip on saturday with the labbed 31 Bravo. I carefully started going into boost so at 5000rpms I had 2-3PSI and 75mph with 23% slip. At 5100 I had 5-6psi and 80mph with 20% slip.

I have 2-3psi left and 700 rpms so it looks promising that the prop will be pretty good with a minor tweaking. The mid range suck with 30-20% but I can live with that if it's fast as hell at wot...:sifone:

I will try having someone to videocam the next ride so I have some more inputs to work with during the winter.


The slip #'s I posted are WOT. The slip % at cruise was closer to 25%. Also, the boat had a nose cone originally when I bought it. I replaced the lower case with a DWP, but didn't see any noticeable changes.

Tres
10-28-2008, 08:18 AM
Griff, Have you tried the Maximus prop with your X Dimension?

Tres, do the Maximus only work good on a step bottom boat? How about a conventional V with a high X?

Yes I have used a few Maxumis props on some applications, Alot comes into play before selecting props, First weight, then center of gravity, That lets my decide what kind of work I need the prop to do . There is center of moment, then there is center of gravity at speed. The idea is to get every thing to work at balance and with correct height, the best prop should make up for short comings or have the least amount of energy used to create any type of lift. When a prop can be used to only create forward movement only you come out of it with a faster set up.

Offshoredrillin
10-29-2008, 07:24 AM
What a great thread, Tres, on an 00 straight hull tiger,500 efi's w/ 615 hp and 670 tq w/ xr's1.50...what could I expect if I switched it to ITS, the boat topped out at 76. I have a feeling that I'm right at the peak of everything for power and dont want to mess up the boat. 76 was with stock 26's and 5100 rpm, I know labbing would get me some extra rpm and maybe another mph.

Tres
10-29-2008, 08:16 AM
What a great thread, Tres, on an 00 straight hull tiger,500 efi's w/ 615 hp and 670 tq w/ xr's1.50...what could I expect if I switched it to ITS, the boat topped out at 76. I have a feeling that I'm right at the peak of everything for power and dont want to mess up the boat. 76 was with stock 26's and 5100 rpm, I know labbing would get me some extra rpm and maybe another mph.

ITS doesnt have enough set back. 12 inch is what is needed with 3 raise. The rear lifting strakes needs a wedge to raise stern PSI, and spend some doe on your prop work. I have similar set ups that could acheive 80 plus, one we did was getting 81.5 on it very best day. Its all in the set up.

Offshoredrillin
10-29-2008, 09:05 AM
ITS doesnt have enough set back. 12 inch is what is needed with 3 raise. The rear lifting strakes needs a wedge to raise stern PSI, and spend some doe on your prop work. I have similar set ups that could acheive 80 plus, one we did was getting 81.5 on it very best day. Its all in the set up.
wow, had no idea, so I would assume imco boxes and of course the props, would the motors have to be moved. How did the one you set up get on plane with the boxes.

Tres
10-29-2008, 10:22 AM
wow, had no idea, so I would assume imco boxes and of course the props, would the motors have to be moved. How did the one you set up get on plane with the boxes.LOng tabs help, but I didnt have any problem.I used the stelling box.

Geronimo36
10-29-2008, 11:53 AM
Tres, on the 36' Apache's I understand they tried boxes and I have no idea what they set drive height at but from what I'm told it made the bow take flight easily and always had to run tab to keep it down. what do you think?

Tres
10-29-2008, 11:59 AM
Tres, on the 36' Apache's I understand they tried boxes and I have no idea what they set drive height at but from what I'm told it made the bow take flight easily and always had to run tab to keep it down. what do you think?They must have not raise the X with the install of the box.Slight CG change but not enough to do that.

Geronimo36
10-29-2008, 12:05 PM
What if you're stern heavy now? Blowers etc...

Offshoredrillin
10-29-2008, 05:33 PM
LOng tabs help, but I didnt have any problem.I used the stelling box.
Thank you Tres, I'll have to see where my next money is spent besides the interior. if the stellings boxes will take it up and back like you said, and then some prop work, might be cool to see what it will do. It would be amazing to hit 80 with the setup, not many Tigers do it with 500's and a straight bottom, also with the cg change it would stay planted a little more. air makes nice photos, I would like to keep the props in the water.

2112
10-31-2008, 12:05 PM
wow, had no idea, so I would assume imco boxes and of course the props, would the motors have to be moved. How did the one you set up get on plane with the boxes.

Have you seen that new standoff spacer for the ITS from Diamond Performance?
Kinda spendy though.

Offshoredrillin
11-01-2008, 02:34 PM
Have you seen that new standoff spacer for the ITS from Diamond Performance?
Kinda spendy though.
I did, but unlike a stellings or imco they dont account for the raised x, you would have to reposition the motors. i'm really digesting what Tres said and might do it down the road, but it may just be easier to buy a 42 or 46 that already has bigger power and 6's.

MOBILEMERCMAN
11-02-2008, 08:37 PM
I did, but unlike a stellings or imco they dont account for the raised x, you would have to reposition the motors. i'm really digesting what Tres said and might do it down the road, but it may just be easier to buy a 42 or 46 that already has bigger power and 6's.

Some enjoy the process. Buy it the way you want to use it would be my suggestion. If you can.

Offshoredrillin
11-03-2008, 09:38 AM
Some enjoy the process. Buy it the way you want to use it would be my suggestion. If you can.
exactly, and this boat set up the way it is gives me great reliable pleasure, I may just take a straight edge to the bottom and lab the props and leave well enough alone, it runs a consistant 5100 5200 rpm, and 70+ full of people and gas...my 20 will be my little water rod, it should be over 100.

Geronimo36
11-03-2008, 11:25 AM
Some enjoy the process. Buy it the way you want to use it would be my suggestion. If you can.

I hear ya! Ever since I did the resto on my Panther and then on this boat I lost interest. Now I just wanna get in and go! :sifone:

I wish you were still in Jersey cause I'd probably ship the boat down to you and get the X set up! ;)

MOBILEMERCMAN
11-04-2008, 02:48 AM
That would be nice.

Just remember to keep your eye on the Fun Meter. That's the gauge that counts the most.