1987 340 EC

[C Coleman]

Proud new owner of a 1987 340 EC. First big, twin screw boat. Bought the boat in March, brought it home (about 50 miles) no problem. Ripped out the 1980's carpet and have been installing new lonseal flooring and it looks great. I went to take the boat out for the first time in a few months (I do run the boat in place regularly) and ran into a problem that I cannot figure out and was hoping someone could help. The boat runs great (only 180 or so hours on new motors - Marine Power 5.7L 350's) when leaving the dock at low speeds in no wake zone. When I throttle up to take off the boat reaches about 7 mph, squats in the water, and just will not go any faster. Both engines do go rev up as if it were moving but the boat does not move. I tested both transmissions from stand still and they turn boat just fine and seem to work fine (at low speeds at least). I open hatch and can see the shafts spinning just fine. The boat just won't move. It's almost like something is holding the boat down at that moment, I have gone in the water and checked the props and shafts as best as I could and do not feel anything hanging on that could be an anchor (crab trap, net). I am very frustrated with the situation and hope someone could provide a newbie some useful information.

 

[Express 390]

Proud new owner of a 1987 340 EC. First big, twin screw boat. Bought the boat in March, brought it home (about 50 miles) no problem. Ripped out the 1980's carpet and have been installing new lonseal flooring and it looks great. I went to take the boat out for the first time in a few months (I do run the boat in place regularly) and ran into a problem that I cannot figure out and was hoping someone could help. The boat runs great (only 180 or so hours on new motors - Marine Power 5.7L 350's) when leaving the dock at low speeds in no wake zone. When I throttle up to take off the boat reaches about 7 mph, squats in the water, and just will not go any faster. Both engines do go rev up as if it were moving but the boat does not move. I tested both transmissions from stand still and they turn boat just fine and seem to work fine (at low speeds at least). I open hatch and can see the shafts spinning just fine. The boat just won't move. It's almost like something is holding the boat down at that moment, I have gone in the water and checked the props and shafts as best as I could and do not feel anything hanging on that could be an anchor (crab trap, net). I am very frustrated with the situation and hope someone could provide a newbie some useful information.

First welcome CSR, and good luck with the boat! It sounds like you have a lot of growth
on the bottom from not moving for a few months

 

[C Coleman]

Thanks for the welcome. Could growth do that? When I went in the water I felt around the hull and I do feel barnacles but its not a solid layer of them. I can feel smooth hull also in between. It makes sense if it is growth though because nothing else has changed. I do plan to do a bottom job sometime next month. I thought about growth but did not think it would stop the boat like that!

 

[Express 390]

Thanks for the welcome. Could growth do that? When I went in the water I felt around the hull and I do feel barnacles but its not a solid layer of them. I can feel smooth hull also in between. It makes sense if it is growth though because nothing else has changed. I do plan to do a bottom job sometime next month. I thought about growth but did not think it would stop the boat like that!

Absolutely ! I'll bet the Props are loaded with barnacles