I have a 1974 seafarer 29. The boat has an outboard motor that sits in a compartment in the back of the boat. The motor drops through a trap door in the bottom of the hull when you want to use it. For this reason, only a short shaft motor will work. The motor will shift into reverse and you can see it churn up the water but the boat will not go backwards at all. I took the prop to a shop that said it was already a "sailboat" prop. I'm wondering if there is more than one kind of sailboat prop and if a different one would help. It is a 15hp motor. Is a more powerful motor the answer? I should add this boat is new to me and the old owner states it didn't go in reverse for him as well. any suggestions would be helpful. thanks..
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Maybe Your Shaft ISN'T Long Enough?
If the motor doesn't extend much beyond the bottom of the hull, the there won't be any reverse thrust below that drives the boat backward. Unfortunately, you may have to try a long shaft that would be made to fit.
If the motor doesn't extend much beyond the bottom of the hull, the there won't be any reverse thrust below that drives the boat backward. Unfortunately, you may have to try a long shaft that would be made to fit.
A couple of thoughts
First of all, can you move the boat backwards by hand. Make sure it isn't hung on some dock line or other obstruction. My somewhat limited experience in that part of the world, tells me that in a lot of marinas, some boats are actually sitting on bottom at low tide. Also, does it not move at all, or just very slowly? Sailboats do not back up well, and all, inboard and outboard, reverse much more slowly than they go forward. Have you checked for a shear pin that could be broken. Also do you hear any kind of clicking or ratting noise that indicates a slipping gear box. This would let the prop turn some, but certainly not enough to move the boat. I would also suspect the shaft length of the motor. If you can see it churning up water, then it is going into gear, but if the prop is high enough that you can see it churning up a lot of water, that doesn't sound right. Water flow should not be what I would call churning. Maybe just a matter of wording here. On my S2, after it had sat a long time after Katrina, the boat wouldn't move forward or reverse. I could see water churning out the sides of the boat, and churning is the proper wording here, but no water moving out the stern. Turns out the prop had so many barnacles on it, just didn't do anything.
First of all, can you move the boat backwards by hand. Make sure it isn't hung on some dock line or other obstruction. My somewhat limited experience in that part of the world, tells me that in a lot of marinas, some boats are actually sitting on bottom at low tide. Also, does it not move at all, or just very slowly? Sailboats do not back up well, and all, inboard and outboard, reverse much more slowly than they go forward. Have you checked for a shear pin that could be broken. Also do you hear any kind of clicking or ratting noise that indicates a slipping gear box. This would let the prop turn some, but certainly not enough to move the boat. I would also suspect the shaft length of the motor. If you can see it churning up water, then it is going into gear, but if the prop is high enough that you can see it churning up a lot of water, that doesn't sound right. Water flow should not be what I would call churning. Maybe just a matter of wording here. On my S2, after it had sat a long time after Katrina, the boat wouldn't move forward or reverse. I could see water churning out the sides of the boat, and churning is the proper wording here, but no water moving out the stern. Turns out the prop had so many barnacles on it, just didn't do anything.
How about motor tilt?
If your motor is tilted so that the prop is forward of the powerhead, the prop will push water into the motor well. I would try tilting the motor so that the prop is behind the powerhead. That will force water down and towards the bow instead of into the motor well. The adverse effect will be that the bow will want to ride higher while in forward with some throttle on. Also becareful of your forward speed if you are trying to dock the boat. Hope that helps. r.w.landau
If your motor is tilted so that the prop is forward of the powerhead, the prop will push water into the motor well. I would try tilting the motor so that the prop is behind the powerhead. That will force water down and towards the bow instead of into the motor well. The adverse effect will be that the bow will want to ride higher while in forward with some throttle on. Also becareful of your forward speed if you are trying to dock the boat. Hope that helps. r.w.landau
Too short
As other said. This is a common problem with outboard powered boats when the shaft is too short. The prop wash is pushing forward against the flat transom which counteracts any rearward bite you're getting from the prop, which may also be reduced by it's proximity to the surface. The prop needs to be lower than the transom, or in your case lower than the front of your engine compartment. If a longer shaft is out of the question for your mounting parameters, you could install a transom mount which will either allow setting your existing motor lower or allow the installation of a longer shafted motor. However with the beutiful lines of the Seafarer you may not want this on your nicely swept transom. You may want to consider modifying or removing your engine compartment doors (if I remember correctly they are vertical?) to accomodate a long shoft engine. A modification to parts can always be undone if desired however a modification to hull or decks is a different story IE: the hideous cuts done to 70's Catalina 27's to put in 4 strokes.
As other said. This is a common problem with outboard powered boats when the shaft is too short. The prop wash is pushing forward against the flat transom which counteracts any rearward bite you're getting from the prop, which may also be reduced by it's proximity to the surface. The prop needs to be lower than the transom, or in your case lower than the front of your engine compartment. If a longer shaft is out of the question for your mounting parameters, you could install a transom mount which will either allow setting your existing motor lower or allow the installation of a longer shafted motor. However with the beutiful lines of the Seafarer you may not want this on your nicely swept transom. You may want to consider modifying or removing your engine compartment doors (if I remember correctly they are vertical?) to accomodate a long shoft engine. A modification to parts can always be undone if desired however a modification to hull or decks is a different story IE: the hideous cuts done to 70's Catalina 27's to put in 4 strokes.
Short or long, angle is everything.
If the cavatation plate is thru the hull opening, the shaft is long enough. try the tilt before you buy a motor. Should be about 5 to 8 positions.(just a guess) r.w.landau
If the cavatation plate is thru the hull opening, the shaft is long enough. try the tilt before you buy a motor. Should be about 5 to 8 positions.(just a guess) r.w.landau
Exhaust Creating Cavitation?
Some motors have available a deflector to prevent this. As the exhaust exits your prop hub the only thing the prop has to bite into is the exauhst. Chec with a dealer for your outboard. Maybe borrow a different outboard to see if is your motor or the boat design doing this. Be sure to let us know how this turns out I'm really curious.
Some motors have available a deflector to prevent this. As the exhaust exits your prop hub the only thing the prop has to bite into is the exauhst. Chec with a dealer for your outboard. Maybe borrow a different outboard to see if is your motor or the boat design doing this. Be sure to let us know how this turns out I'm really curious.
if shaft's in the water you should get propulsion
I agree with many of the posters about angle -- I used to have a MacGregor 25 and when the outboard was in reverse it would force the outboard out of parallel with the surface of the water. So it was essentially trying to move the boat up, not backwards. I reinforced the motor in such a way as to make sure it pulled the boat straight back and that helped a lot. If that's the case, it would make sense that you'd see a lot of cavitation -- the surface of the water is being sucked into the prop.
I agree with many of the posters about angle -- I used to have a MacGregor 25 and when the outboard was in reverse it would force the outboard out of parallel with the surface of the water. So it was essentially trying to move the boat up, not backwards. I reinforced the motor in such a way as to make sure it pulled the boat straight back and that helped a lot. If that's the case, it would make sense that you'd see a lot of cavitation -- the surface of the water is being sucked into the prop.
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