"In Sydney Australia it is now
"In Sydney Australia it is now the middle of summer and I hope that some of you guys in the US are still reading these posts, during your winter.
I have an Australian 26'Mariner 30 years old, weight 3.5 tons with a Chrysler LM 318. The boat appears to be like your Trojans and in fact looks quite similar to FastJeffs boat, by the picture.
The max speed was 12 mph, I fitted trim tabs, and got a slight improvement but still would not get on the plane.
I took some advice and changed the prop from a 3 blade 15 inch by 17 pitch, to a 4 blade 15 inch by 15 pitch. The difference was astounding. The boat now has a wot top speed of 28mph at 4200 rpm,with no flat spots or any cavitation. It gets on the plane at 13 mph at 2300 rpm and cruises really well at 14.5 mph at 2500 rpm.
The problem is that once on the plane the boat will not steer except for straight ahead, it requires enormous force on the wheel to change direction to the extent I think something is going to break. To change direction I need to slow down to alter course.
Even worse, in a following sea the boat surfs, and immediately tries to commit suicide by veering quite sharply to starboard and trying to broach.
This is happening with the trim tabs fully withdrawn.
The only way I have found to overcome this is to speed up and try and stay on the back of the wave in front, but inevitably the following wave eventually gets me, and it seems sometimes dangerous to be speeding to stay in front of even quite small waves.
The Rudder is located only 1.5 inches from the prop and the rudder is very small. It appears that as I never had the problem before that it is either the speed that the rudder can't handle, or the increased volume of water going past the rudder that makes it hard to steer.
I now don't know whether to go for hydraulic steering, or do I need a new rudder set up of some kind, or is something else going on altogether that I am missing entirely.
Has anyone else had this problem ? Is there any advice that you may be able to give me. Any assistance at all will be sincerely appreciated."
"In Sydney Australia it is now the middle of summer and I hope that some of you guys in the US are still reading these posts, during your winter.
I have an Australian 26'Mariner 30 years old, weight 3.5 tons with a Chrysler LM 318. The boat appears to be like your Trojans and in fact looks quite similar to FastJeffs boat, by the picture.
The max speed was 12 mph, I fitted trim tabs, and got a slight improvement but still would not get on the plane.
I took some advice and changed the prop from a 3 blade 15 inch by 17 pitch, to a 4 blade 15 inch by 15 pitch. The difference was astounding. The boat now has a wot top speed of 28mph at 4200 rpm,with no flat spots or any cavitation. It gets on the plane at 13 mph at 2300 rpm and cruises really well at 14.5 mph at 2500 rpm.
The problem is that once on the plane the boat will not steer except for straight ahead, it requires enormous force on the wheel to change direction to the extent I think something is going to break. To change direction I need to slow down to alter course.
Even worse, in a following sea the boat surfs, and immediately tries to commit suicide by veering quite sharply to starboard and trying to broach.
This is happening with the trim tabs fully withdrawn.
The only way I have found to overcome this is to speed up and try and stay on the back of the wave in front, but inevitably the following wave eventually gets me, and it seems sometimes dangerous to be speeding to stay in front of even quite small waves.
The Rudder is located only 1.5 inches from the prop and the rudder is very small. It appears that as I never had the problem before that it is either the speed that the rudder can't handle, or the increased volume of water going past the rudder that makes it hard to steer.
I now don't know whether to go for hydraulic steering, or do I need a new rudder set up of some kind, or is something else going on altogether that I am missing entirely.
Has anyone else had this problem ? Is there any advice that you may be able to give me. Any assistance at all will be sincerely appreciated."