Dhadley, I need advice....

[walleyehed]

I broke my stingray off a few days ago, and before I put a new one on I took the opertunity to test 11 different props today.<br /> I have an 18gal built-in tank and a 6 under the back. I filled only the 6 and ran each prop from A-B, and B-A, varying trim as needed. After each prop test, I refilled the 6 so I would be testing exact weights.<br /> I found some very interesting things happening that make me have to say; who ever said "a prop is only for propelling", is missing the boat.<br /> I tested some of these props earlier with the foil on, and with the engine mounted in 3 different heights.<br /> Over-all, the boat sucks coming out of the hole compared to how it comes out with the foil- I got REAL spoiled with that fin!<br /> The part that spun my brain was the fact that certain props worked BETTER without the fin as far as top-end and hull angle goes-without porpoising, and then 2 others I couldn't trim past level and NOT porpoise.<br /> Now for the advice.....would adding set-back help my performance on this deep-vee, or would I be waisting time???????<br />1997 115 Jonny, 18ft Starcraft.<br /> I wish I could type smaller, but I got my highest-ever speed tonight on a prop that has always given excellent hole-shot and midrange, and it occured without a fin!!????........<br /> I got 48MPH out of this thing-a consistant 48.<br /> Should I leave well enough alone??<br />TIA, Kenny

 

[Dhadley]

Re: Dhadley, I need advice....

Generally speaking, we find that a setback helps to some degree. A setback influences things in several ways -- <br /><br />1- It changes the center of gravity (lengthwise). This is good if the boat needs bow lift. Keep in mind that you can move the center back too far also. This balance is what we look for.<br /><br />2- Because the water comes off the hull at an angle and the transom is made on an angle, the further you move the propeller back the higher you can mount the motor. Thus reducing drag.<br /><br />3- The setback will allow you to find the "sweet spot" in the water. This is not always right up aginst the transom on some boats. Sometimes moving the prop back moves it into less turbulant water where it gets a better bite.<br /><br />4- Using a jackplate as the setback (as opposed to a solid bracket) allows for quick height (X dimension) adjustment while testing.<br /><br />I think a jackplate would probably help your boat. I like the Bob's plates personally. In this case if you were looking for a manual plate I would start with the 6" convertable. It can be set at 6" or 3" setback. He also has 2" spacer blocks so you could go as far back as 8". It has 6" of verticle adjustment. Without a low water pick up this is more than enough. <br /><br />If you wanted to go right to a hydraulic plate I would go with Bob's 6". As light as the Starcrafts are you probably wont need the 10" plate unless the boat is real bow heavy. It depends on which model boat and which 115 you have you have.<br /><br />As an example, I had a 6" hydraulic on my Hydrostream. With a 200 OMC looper on a 20' air entrapment hull we certianly didnt need more bow lift. On my 20' Dusky I have a 10" because the motor is light (60 degree 150) and the boat is very heavy, especially in the bow.<br /><br />Those Permatrim Hydrofoils look pretty good (although I hesitate to call a fin a hydrofoil).<br /><br />Good job with the testing, it takes a lot of patience to test that many props. Interesting, huh?<br /><br />Keep us informed!

 

[Jdeagro]

Re: Dhadley, I need advice....

Walleyed;<br /><br />Your research was extensive, and the results informative, and beneficial. As you know I am the one who says that the "prop is for propelling" and I stick by that. However, this does not mean that choosing the correct prop for the specific boat won't give better results, and prop design will change the handling of the boat. <br /><br />In our testing we start with a factory recommended prop and run low speed tests, acceleration test, top speed tests, fuel consumption test. <br /><br />WE then run the same tests under the same conditions with the Smart Tabs, and adjust them to the best overall performance. In every case the boat is improved, including hole shot, time to plane, top speed, and elimination of porpoising. Typically the boats run 2 to 4 mph faster at WOT.<br /><br />Since we have a good relationship with a number of prop manufacturers, we then started to run test with various props (with and without the Smart Tabs).<br />Depending on the design and material ( aluminium, or stainless) the boat reacted differently. In all cases the ability to combine the "adjustable tab lift pressure" with the most efficient prop, resulted in improving the boat performance even more. Typically adding another 2 MPH. <br /><br />Keep in mind that Smart Tabs are designed to improve the "mainstream boat" performance, not an off shore race boat, or a boat that is designed for one specific speed or condition. I would never recommend them for a Master Craft Ski boat. <br /><br />You will never know until you try them. You and DHadley have tons of very valuable experience with other products, but apparently none with Smart Tabs. I would be happy to work with either of you at any time.

 

[walleyehed]

Re: Dhadley, I need advice....

NautiJohn, I couldn't remember where I seen the "propelling" before...now I know-no insult intended, just couldn't believe what I came up with trying so many diff. props.......<br /><br />Dhadley, I have a cross-flow. Also, I completely refurbished this boat. I added a 74lb. thrust minn kota up front-62" shaft, and 2 group 31 batts between the consoles under the platform...thats where my platform starts, so I have a bow-heavy boat, and I've known that.<br /> I like the idea of playing with set-back-one of those things you get in your head and aren't satisfied till ya try it type deal.......

 

[Jdeagro]

Re: Dhadley, I need advice....

Walleyed<br /><br />Did not mean for my response to sound defensive or curt. I just believe that too much emphasis has been put on the use and design of props to do work that should be done by the hull. The way these small boat pound in minor chop ,it is a wonder that Preparation H isn't sold in marine store. Maybe that is our next new product!

 

[Dhadley]

Re: Dhadley, I need advice....

OK. You have the heavier of the two 115's offered that year. Thats good in a way. When adding the set back you will be transfering slightly more weight. <br /><br />Do you have the center console model?

 

[walleyehed]

Re: Dhadley, I need advice....

Dual console........K

 

[Dhadley]

Re: Dhadley, I need advice....

What model is that -- the Super Sport?

 

[walleyehed]

Re: Dhadley, I need advice....

1979, and yes, I believe it was the super sport. it was on the original glove box, and I don't remember.....seems like super sport 18?????<br /> Anyway, 80" beam-narrow by new standards.<br />Has the HUGE splash-well...you can't hardly see the top of the engine when you are setting down in the seats.

 

[Dhadley]

Re: Dhadley, I need advice....

We used to be a Starcraft dealer and sold a bunch of them. The center console was very popular here. I had some 18's and a couple of the 21's. Neat boats. We put a 200 (with a 150 hood naturally) on one of the 21's and used to ride up river and outrun the ski boats. They didnt much like it when a big ol' fishing boat was faster. Funny how they never thought of the Starcraft as being so much lighter.<br /><br />Too much fun!

 

[walleyehed]

Re: Dhadley, I need advice....

The starcraft factory was very helpful in my refurbishment prossess of this boat and I've had many people ask what model is that??? I put my own paint scheme on, and put stock STARCRAFT decals back on.<br /> As you know, I've done a fair amount of "playing" with this set-up and it's great to pull up next to a boat of simular size with maybe a 125-130hp, and just walk off like they're setting still.!!<br />It is fun!!!!!!