Dhadley, transom extension

walleyehed

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Jun 29, 2003
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Dhadley, I'm attempting to build a fixed setback on my Starcraft.<br /> It's 6061 aluminum channel 3/8"X 5"...the sides are 3.25", which will be the mounting surfaces.<br /> The question I'm asking myself, and you, is, Is this enough of a footprint on the transom to be stable??? And, should I use 2 bolts at the top on both sides for stability? the one I have seen, and I don't recall where, had 2 holes at the top and one at the bottom on each piece of channel.<br /> I also have a 5/8" resin impregnated piece of plywood on the transom now....should I leave it, and mount the channel on top, or should I remove the wood????????? seems like it would be stiffer if I left it...??? what'ya think?? :rolleyes:
 

Solittle

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Apr 28, 2002
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Re: Dhadley, transom extension

I would like to help but not my area of knowledge. To help anyone who has you might indicate how big a motor you are planning to mount and how big a boat that you are putting it on. I mention this as 5/8" ply dosen't seem much support for anything other than a small motor.
 

walleyehed

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Re: Dhadley, transom extension

I have a 2" thick transom, with the 5/8" as a mounting platform to help distribute the load.<br /> I have an 18ft Starcraft Super sport 18, deep-v, with a 1997, 115 Johnson on the tail....It's built for a 150. I'm in 3rd hole and can see the water line at WOT is still higher than needed-right on cavitation plate.......<br /> I've been talking with Dhadley on some issues with this boat, and was looking for opinions on set-back......... :)
 

walleyehed

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Re: Dhadley, transom extension

Dhadley, ya home yet????? Did ya get to see speed, or Mike Medart?????<br /> I would have loved to had the time to go........oh well....<br />Let me know what you think of this...(I've already tried it out, and it's been interesting) :D :D
 

Dhadley

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Feb 4, 2001
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Re: Dhadley, transom extension

You ended up with 5" of setback, right? That sounds like a pretty good starting point. Were you able to raise the motor any?<br /><br />How did the boat react to the motor relocation? Was the water pressure still OK?
 

walleyehed

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Re: Dhadley, transom extension

Nose doesn't drop as much, and yet it doesn't porpoise. seems to be very stable and the water pressure hasn't dropped, so I'm going to try one more hole up. The stingray is above the waters surface on plane now. so far, a little speed, maybe 1 mph, and very little RPM change. It handles differently in turns-not bad, just different. I'm going tonite again, so I will post then......THX :)
 

walleyehed

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Re: Dhadley, transom extension

Dhadley, Back from another excursion...tonite was a pleasant surprize. I blasted off from the NO WAKE ZONE and could tell right away, it was different again-after going up to second hole on setback for tonites run.....I can see at this point, I'm going to have to leave the stingray at home....I don't think it's needed anymore, but of course I will try again before I remove it.<br /> Tonites figures are the biggest single jump I've had so far....Same two guys in the boat, same fuel load, I gained an EASY 200RPM, and I have no ventilation in the turns unless I turn harder than what is normal. I run 8 miles playing with the trim, and notice it doesn't require the same amount (trim), and again, not bad, only different.<br /> One thing I also noticed is at optimum performance, the boat has zero torque and seems to be a little more stable, handeling wise.<br /> I've lifted motor already, tonite and will try tomarrow night. If RPM goes up anymore, I'm going to have to change props again.<br /> With setback, is there any particular situation to look for and avoid??????? I don't like surprises in handling.<br />Thanks again, for the comments and help....I feel like I'm gaining quite a bit here, and I can't help but grin about it...I thank you for that!!!<br /> I'll keep ya posted! :D :D
 

Dhadley

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Feb 4, 2001
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Re: Dhadley, transom extension

Everything you said is what we look for -- zero torque, less positive trim to achieve the same ride attitude, good water pressure and more speed. <br /><br />You are doing exactly what we would do -- go up slightly and test again (great excuse to go boating).<br /><br />I'm sure you mentioned but which 115 do you have? The crossflow or the 60 degree looper? What RPM's are you at now?<br /><br />Nice work on keeping the same test load.
 

walleyehed

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Re: Dhadley, transom extension

This is a crossflow-97' model.<br /> I'm looking 5800 in the face, if it jumps more, I'll go up one more step in pitch.<br /> Also, I think I'm goimg to leave the stingray home tonite.....I should do the next test with it, but I think it has too much against it now.<br /> I don't think I'm getting the benifits like it was on the transom. :)
 

walleyehed

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Re: Dhadley, transom extension

I'm back.......and i left the stingray on for the first test. Boat still planes very easily-matter-o-fact, don't notice any difference there.<br /> I gained another 150RPM, and 1-2mph. It ventilates in the turns if left at max trim fwd-straight-line, very stable.<br /> I went from my Nauticpro 13-3/8X17, and put my 13.5X18 Raker on....I know these 2 props are for different set-ups, but I had to try the raker.<br /> First, the 17", trimmed down pulls 5200...trimmed for max performance, I'm pushing 6000r's.<br /> Second, the Raker trimmed down, (still good hole-shot) shows 5000...trimmed for max, I'm showing almost 5500....BUT, I tried to trim just a little farther to see what it would take to ventilate, and slow down. I trimmed a touch at a time, and a few touches later, it appeared to start to ventilate, but I had no speed drop...it went up! a touch or 2 more, and higher RPM yet, and still increasing in speed.<br /> about 5700-5800r's with Raker, but will porpoise before ventilation is to the point of loosing speed.<br /> Yes, I left the stingray on, but don't believe it works much out of the water?????????<br /> With the 2 props at this point, I feel the 13-3/8X17 is performing best right now as the speeds are nearly equal, but I am turning the 17" 200r's more.<br /> I'm still pissin' a strong stream of water with no indications of water pressure lowering at this point.<br /> My thoughts tonite: What the heck, I'm going up 1 more.......<br /> Boat overall rides much more stable for just a simple setback, and changing the hieghts of mounting. I'm very pleased with my gain even if I get no more......I'm still grinin'....... :) <br />BTW, I ran into a gent from Texas with a Bass boat w/150hp, 1996 fastrike, and I talked with this guy for about an hour about what I was testing....interesting conversation, and I'm going to list another post on what was said, and this will be posted under J/E, as it pertains mostly to that...Be looking! :) :)
 

CalicoKid

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May 27, 2002
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Re: Dhadley, transom extension

Walleye, I've been watching your progress here. What was your top speed before you started this project and what is it now? Can you show a picture or a link of your setback's design? I've been considering such a setup for my 16' Baja. Have fun, be safe.
 

kenneths

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Oct 3, 2003
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Re: Dhadley, transom extension

Back for another report....If you haven't caught any of my other posts, I have not been able to get on last week due to PC being down.<br /> Anyway, If I raise anymore, I'm going to install a new water pressure gauge, mainly because the last outing, It stuck at 18psi, and is inop at this time.<br /> To answer a question, I've gained an honest 4mph, and about 6mph with the RAKER. I know the closer I get to 50mph, the better the RAKER is.<br /> My concern at this point is water pressure-as soon as I get a set-up installed, I'll go to 4th hole-the way I built my setback plate, I'm 1 hole higher than transom in the first hole.<br /> I've got to say, this has SUBSTANTIALLY changed handling for the better, and didn't know I could be this much happier with this boat without adding another 35 horse. I'm VERY happy with the 49-50mph I see now. I started in the 44mph range, and have been playing with props all-over again.<br /> One other item I've found that may be of interest to some...the ONLY prop in aluminum I've found that will "bite" at this height, is a TYPHOON, by Merc.......Don't sell Merc props (OEM), but this prop will hold when the OMC alums. won't. Michigan wheel won't grab either.<br /> The RAKER really likes this set-up....I can run FULL-UP trim and it doesn't cut lose, or slow down-what a prop! For nearly 500.00, it should be........ :)
 

kenneths

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Oct 3, 2003
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Re: Dhadley, transom extension

Crap, I forgot to mention, I will add pictures when I get my PC at work back up....my camera is there.
 

walleyehed

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Jun 29, 2003
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Re: Dhadley, transom extension

Went to hole #4 tonite.....too much.<br />Had to leave it full down or it would ventilate.<br /> I may try another inch back, and try the 4th hole again, but I think I already found the sweet spot in the 3rd hole.
 

Dhadley

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Feb 4, 2001
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Re: Dhadley, transom extension

Sounds good! Drop one hole and go boating....er....I mean testing.<br /><br />Ya gotta love it!
 
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