Finding the best X-dimension

[Geronimo36]

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]

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]

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]

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]

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]

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]

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]

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]

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]

Here is IMCO spacer page

http://www.imcomarine.com/pages/ster...rive%20spacers

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

[Tomas Wallin]

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]

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]

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]

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]

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...

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

[Griff]

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...

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]

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]

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]

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]

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.