Any help appreciated... I just got an '06 aluminum Triton 17 sport; motor is 75hp Optimax... Anyone have any advise on what sixe / pitch for the prop. It has a SS Stilletto on it now; no markings on the prop so I do not know the pitch. Max RPM is 5000 however the boat porpoises extremely bad going thru 4K.. any advise appreciated...
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Triton Tourny Sport 17 - porposing
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bassin4fun
Active member
+1.....turbotodd said:
trim 'er down some.
PSG-1
Well-known member
I've got a 2007 Triton 1650SC, and if you trim the engine up the slightest bit, it wants to porpoise, or even cavitate, even with a hydro-foil on the engine. If I keep it trimmed down, I don't have that problem, but, dang, I know that's got to be costing me some top end.
Of course, you have to account for the fact that the 50HP engine weighs 200 lbs, then, there's 24 gallons of fuel, for another 240 pounds, then a trolling motor battery, and the cranking battery, that's another 100 pounds.....so, there's already almost 550 pounds sitting in the stern of the boat, and that's BEFORE the weight of the operator and a passenger. Just a crappy layout from the manufacturer.
My parents have an 18 foot Sea Hunt with a 150 Optimax, at full throttle, you can trim the engine until it's shooting a roostertail 50 feet into the air, and the boat does not porpoise one bit....now THAT's a properly balanced boat, unlike my Triton.
About the only way I see to eliminate the porpoising (at least in my case) is to modify the boat and move both fuel tanks and batteries to the front. That would put about 350 pounds to the bow, which would equal out the weight of the engine at 200, plus my weight at 160. I keep thinking about doing this modification, and sooner or later, I'm going to end up doing it.
Of course, you have to account for the fact that the 50HP engine weighs 200 lbs, then, there's 24 gallons of fuel, for another 240 pounds, then a trolling motor battery, and the cranking battery, that's another 100 pounds.....so, there's already almost 550 pounds sitting in the stern of the boat, and that's BEFORE the weight of the operator and a passenger. Just a crappy layout from the manufacturer.
My parents have an 18 foot Sea Hunt with a 150 Optimax, at full throttle, you can trim the engine until it's shooting a roostertail 50 feet into the air, and the boat does not porpoise one bit....now THAT's a properly balanced boat, unlike my Triton.
About the only way I see to eliminate the porpoising (at least in my case) is to modify the boat and move both fuel tanks and batteries to the front. That would put about 350 pounds to the bow, which would equal out the weight of the engine at 200, plus my weight at 160. I keep thinking about doing this modification, and sooner or later, I'm going to end up doing it.
thanks guys for the advise...yes...all the weight is in the rear of the boat..... I just thought that maybe there was somethoing I could do ..smaller prop, hydrofoil, etc to get more top end without the porposing..don't want to do any reconfiguring of the boat...just htought the boat would be beter engineered to not porpoise so much... thanks
bassin4fun
Active member
just put a friend and a big ol' loaded cooler in the bow....... :beer:
Can also go to a prop that gives a little more stern lift. May not cure it totally but sometimes it helps. Ive also seen props with some cupping help as well, but that was an extreme case where it would pitch the bow up, then down, but as it came down the prop would blow out. Adding cup to the prop solved his problem (aluminum bass-style boat with the motor mounted higher than it really should have been). His original complaint was the bouncing and 50-80' tall roosters, and slower than normal top speed. If the rooster is much more than 5-8 feet, it's a waste. Cool to watch but generally on most outboard boats, a waste. Roosters are usually caused by the prop tips coming up out of the water a little. That's why ventilation (blow out) can be an issue if the prop is not correct on such boats.
thanks agin...I am goimng to try a smaller prop...really don't know this size on it now but will have the dealer check it out and give me a smaller pitch...with motor trimmed down to prevent porposining 5000 rpm is all I can spin...should at least be able to get 5500...
we'll see...
Again, thanks for all the help...this is a great informational website for tin boats
we'll see...
Again, thanks for all the help...this is a great informational website for tin boats
