Hello All,
I've got a new to me 2000 Javelin 18FS with a Johnson 150. I'm probably the third owner and a previous owner had trim tabs and hydrofoil on it. When I got it, the hydrofoil and trim tabs had been removed. They were removed prior to the owner before me. The boat runs great and is in good enough shape for the money, heck, long as it floats and runs it's good for me.
Trouble is it porpoises really bad even on pretty calm water. I haven't had it on glass smooth water, but it seems to start porpoising even in the lightest chop. I had it out a dozen times tubing with the kids and wanted to get it on plane faster and at a slower speed so I put a hydrofoil on the cavitation plate and it really really made a remarkeable difference. However, now if I have it trimed down too much, the boat lists to the passenger side when at speed. Trim up too much and it lists to the driver side. When it's trimmed what I think is about right, it rids pretty balanced left to right. That sounds like a good thing to me as it works about like a trim guage. However, that is also when it starts to porpise if I give it much speed. Around 35-45mph is where it starts to porpoise and the motor is only running about 3500-4000 rpm and could go a bit more. I think WOT is listed as 4500-5500 in the engine manual, but I don't have it handy at the moment.
It was bad about porpoising before the hydrofoil, but with the hydrofoil I get the side effect of listing left if trimmed too far down and listing right if trimmed too far up, but I don't think that would have anything to do with it.
The only other boat I've ever had was a 15ft 40hp with a hydrofoil that runs about 29mph if I'm lucky. I have it manually trimmed (no electric) and water has to get rough for it to porpoise. What is odd is the old boat is a flatter bottom tri-hull where the Javelin has more of a center V to it.
Anywho, after all this babble, does anyone else have the same problem or any tips or solutions? Would trim tabs be worth putting back on it?
Thanks in advance!
Lynn
I've got a new to me 2000 Javelin 18FS with a Johnson 150. I'm probably the third owner and a previous owner had trim tabs and hydrofoil on it. When I got it, the hydrofoil and trim tabs had been removed. They were removed prior to the owner before me. The boat runs great and is in good enough shape for the money, heck, long as it floats and runs it's good for me.
Trouble is it porpoises really bad even on pretty calm water. I haven't had it on glass smooth water, but it seems to start porpoising even in the lightest chop. I had it out a dozen times tubing with the kids and wanted to get it on plane faster and at a slower speed so I put a hydrofoil on the cavitation plate and it really really made a remarkeable difference. However, now if I have it trimed down too much, the boat lists to the passenger side when at speed. Trim up too much and it lists to the driver side. When it's trimmed what I think is about right, it rids pretty balanced left to right. That sounds like a good thing to me as it works about like a trim guage. However, that is also when it starts to porpise if I give it much speed. Around 35-45mph is where it starts to porpoise and the motor is only running about 3500-4000 rpm and could go a bit more. I think WOT is listed as 4500-5500 in the engine manual, but I don't have it handy at the moment.
It was bad about porpoising before the hydrofoil, but with the hydrofoil I get the side effect of listing left if trimmed too far down and listing right if trimmed too far up, but I don't think that would have anything to do with it.
The only other boat I've ever had was a 15ft 40hp with a hydrofoil that runs about 29mph if I'm lucky. I have it manually trimmed (no electric) and water has to get rough for it to porpoise. What is odd is the old boat is a flatter bottom tri-hull where the Javelin has more of a center V to it.
Anywho, after all this babble, does anyone else have the same problem or any tips or solutions? Would trim tabs be worth putting back on it?
Thanks in advance!
Lynn
