Finding the best X-dimension

[2112]

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]

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]

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]

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]

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]

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]

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]

OSdriling,
Why would you change from 6's?

 

[Offshoredrillin]

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]

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]

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]

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]

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]

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]

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]

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]

Tres,
Welcome and thanks for sharing.

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

 

[Offshoredrillin]

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]

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]

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.