Sec Agent Man

Hello fellow Daytona owners, this is the Secret Agent Man. I am new to the offshoreonly site but could use a little information. I have a 2001 25' Daytona that runs 127 mph. I am interested in putting a 1" or 2" shortie drive. If anyone can help me out with information or advice it would be appreciated.

Also I am going to the Eliminator Regatta at Lake Havasu in May. My family and I are from Virginia, so this will be a long trip. I hear it's a lot of fun. Would like to hear from others who are going. Looking forward to meeting some of you online and at the Regatta.

Cattitude

S.A.M. - sounds like you should be giving us info!

Is your hull twin or single step- it is relevent as the x is different and so is the center pod.

Mine's a twin, I've now got the 2" shorty with a half inch spacer installed. I have not run this set-up yet but hope to soon. The lake I live on is up 8' in the last 10 day which means all kinds of stuff floating in the middle of the lake- need a few days for the stuff to migrate to the shorelines.

will advise results.

Sec Agent Man

Well, I had a 25' V-bottom that ran 103, took the information I had and applied it to this one. I could still use a few lessons. My Daytona is a single step hull, I have not run a shortie drive, my x dimension outdrive gimble is 2-1/2 inches under the bump rail which makes it very deep in the water. The key factor is making the prop lock up. I run a 34 pitch lab finish bravo, slip is 15% which is extremely high, perhaps with a little more finesse we can achieve in the mid 130 range.

If I wasn't the Secret Agent Man, I could tell you a few more things, but I can't, breaks the code.

Cattitude

S.A.M.- There's a guy on the board- Steve snider I think, from Indiana I believe that is in the marine biz and runs a 25' single step. Last fall I was talking with him, he had been running a 1" shorty and was about to go with a two inch shorty based on the planing characteristics etc of the 1". he would be a good person for you to speak with- he often has something for sale in the outdrive section. Have you discussed the shorties with Jerry May at Eliminator?

I'm about 1/2 way to your Havasu trip from Virginia, about 70 miles North of ft. smith/I40, In case you feel the need to stop and play.

Cattitude

Update- I installed the 1/2" spacer yielding a 1.5" shorty, lost my 230 lb passenger and the extra battery, running about 80 gallons vs 100 about 10 days ago. Similar air water and wind.

94.1 GPS on the rev limiter (5400)! As a reminder 10 days ago was 89.1 all porked out and last year's best with standard Bravo prop and drive, similar conditions running me and 15 gallons was 87.9.

Now low 90's comes fast and i have to finesse that last couple digits.

The 1/2" spacer made a big difference in planing, a 1" spacer (to yield a 1" shorty would likely be best for fellow recreational guys but I suspect I'll get a decent deal on the this 1/2" one from the guy who let me borrow it.

All this from a little 454 mag with a whipple! I'm probably done tweaking for now, will keep my eyes out for a deal on a labbed 30.

Uncle Toys

Cattitude – Congratulations! Couple of questions. First, with the 1 ½” shorty, where is your prop shaft in relation to the bottom of the boat. I read above where you said it is ¾” below the sponsons, but yours is a single and therefore in the middle. You must be talking about the center pod? T2x and Philip have been convincing me that my prop shafts should be 1 ½” above the bottom of the boat. Tried to measure that, but its tricky with the steps. Going to try and catch Jerry May at the lake and have him take a look at it. Second, didn’t you say you’re on the rev limiter with the new labbed 28”? If so, it wouldn’t help going to the labbed 30”, would it? Or do you have extra throttle at the rev limiter?

Bottom line, that’s real kewl! Worried that those last 6mph are going to haunt you. Maybe switching to the 1.50 gear?

Cattitude

UT- could be you're a little dislexic (Could not even find that one in the dictionary) this morning 1.50 gears and smaller props would slow the boat down if I'm on the rev limiter now. the 30 lab would likely pull r's down 200 or so and squeek out a couple MPH- a cool weather prop as the 28 will likely be a good hot weather prop.

I'm tickled to have a solid 90 MPH boat, especially given the tame reliable nature of my setup. I'd rather be slower and reliable than the fastest and getting towed in.

The prop shaft height I spoke of earlier is relative to the bottom running edge of the outer sponsons, with the 1/2" spacer it would now be 1.25" below. I uses a relatively scientific method, used two long straight edges and a visual plane- it's as close as you can get without a CMM or Jig.

Keep in mind the worthy advice you're getting is for twins and I suspect the majority of their experinece is on longer east coast cat hulls. every boat is different- especially single vs twin.

Uncle Toys

Cattitude – I’m certainly not dislexic (or dyslexic), although I definitely have trouble reading at times.

Mark at BAM made a case that 1.36 gears are “too much” for my boat and I should be running 1.50. The explanation was to far over my rookie head. However, actual testing has proven Mark to be the winner on prop advice for my boat – over the likes of Bob Leach and Jerry May. Thought you might have better luck understanding his explanation.

On the prop shaft depth – I am totally confuse. Next time at Eliminator I’ll check out a twin step 25’ so I know what I am talking about.

Sec Agent Man

Hey Uncle Toys, to determine your X-dimension, 1st you must level your boat, then level your drive, take a small piece of string and tape it to the back of the bottom of the sponsons. Take a square and measure the center of the prop shaft to the string, that will give you a good idea of your height of your x-dimension.

I've talked to Jerry May and I cannot get good solid information from him on optimal drive height. Do you think it's because I'm on the East Coast instead of the West Coast?

Changing your gears to a 1:50 and running a 30 pitch prop will increase your mid-range and maybe gain a few mph on top. I have experienced 454's lose mph with 1:36 gears, requiring more torque to turn them. Yes, in general, 1:36 gears require more torque, 1:50 gears may be suited for you.

Does your engine have a hydraulic cam? If so, perhaps you can wring it out to 6,000 rpm. More rpm equates to more speed. Don't be afraid to let the motor wind out.

Here is a formula for you to use to see what your prop slippage is as oppose to mph.
RPM X Pitch divided by Gear Ratio divided by 1056 = theoretical speed minus that by percentage and you will see what your % of slippage is.

I have a 25 Daytona, single step hull, a blown 540 running 127 mph. Looking to install a 1" or 2" shorter drive. Are you going to the Havasu Regatta?

S.A.M.

Uncle Toys

S.A.M. – Glad you brought up the Regatta, I had forgotten about it. Going to discuss it tonight with my wife and daughter. I’m sure it would be a slam dunk except its Mothers Day weekend, so…..

I can’t imagine Jerry May would treat you differently because you’re on the right coast – he’s definitely not that kind of person. Actually, I haven’t notice an attitude from the left coast towards the right coast at all. Might try calling John Behman (sp?) at Eliminator. He is Jerry’s rigging partner (most of the time).

Torque could be the difference Mark at BAM was talking about considering my boys are still natural breathers. So Cattitude, maybe it doesn’t apply to you considering your enhance lung capacity.

Your method of measuring the prop shaft depth sounds like the best I have heard so far. But one question, how do you level your boat? What do you use for the reference?