| Author |
Message |
    
Derek Schulze
Member
Username: biffidum
Post Number: 15
Registered: 06-2009
| | Posted on Sunday, June 21, 2009 - 01:27 pm: | 
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OK me again with another question. I have this 70HP Merc on a 14' Grew boat. The boat tilts port side when above 1/4 throttle - obviously the more throttle the more the tilt. I have adjusted the trim tab all the way to the right (starboard) and little has been affected. The steering seems balanced no pull. I moved the trim tab all the way to port and still the same symptom. The skeg is missing about 2" from an encounter with terra firma (not my bad).
I have measured the motors position on the transom and it seems more or less centered (maybe tilted 1/4" to the starboard at the bottom (I can't straighten it more as the lower mount holes were drilled in this position.
I am running a smaller prop 10 3/8x 13 pitch prop which is middle of the road on this motor. The boat sits level in the water when not moving so the load is balanced. There does not appear to be anything way out of whack when I eyeball the hull.
I am assuming this is from prop torque. I don't want to spend a fortune so no motorized trim tabs are an option. I could make a trim tab and mount it on the port side of the transom to lever it up when the boat is under way. Before I do this is there anything else I should be looking for?? |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5432
Registered: 05-2007
| | Posted on Sunday, June 21, 2009 - 05:07 pm: |
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That sounds like alot of horses for a 14' foot boat.
You may need to go to a fixed trim tab on the transom (or smart tabs etc) to compensate for the over torque from the motor.
What model is your boat? |
Derek Schulze
Member
Username: biffidum
Post Number: 17
Registered: 06-2009
| | Posted on Sunday, June 21, 2009 - 07:32 pm: |
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Grew SS140 |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5442
Registered: 05-2007
| | Posted on Monday, June 22, 2009 - 10:34 pm: |
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So a heavy fiberglass job from the 80's (or earlier).
Fixed tabs may be your cheapest option but they can give you a hard time in following seas. Smart tabs are the "in between" option, but will still run ya 150 bucks or so.
Keeping a firm grip on the steering wheel, while a pain sometimes, is the no cost option. |
Michael McPeek
New member
Username: virgil
Post Number: 1
Registered: 07-2009
| | Posted on Friday, July 03, 2009 - 11:45 pm: |
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A "Dol-Finn" with its added trim tabs may help to stabilize the boat also. It should help with the porpoising that I would imagin such overhorsepower would create also!!! |
Derek Schulze
Member
Username: biffidum
Post Number: 24
Registered: 06-2009
| | Posted on Monday, July 06, 2009 - 08:43 pm: |
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I put a set of Nautix automatic trim tabs on it and it ran beautifully - till I lost a piston ;-) |
Graham Lamb
Senior Member
Username: galamb
Post Number: 5544
Registered: 05-2007
| | Posted on Monday, July 06, 2009 - 10:02 pm: |
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Lost a piston once, but after an exhaustive search found that it had rolled off the bench and was hidden behind the trashcan  |
