Manual Trim preference

[Jack09]

So I took my SR4 out for the first time with the family yesterday and loved it. It was with my wife and young daughter.

I have a 40hp Mariner with no electric trim. The trim is currently set on the middle hole of 5 which is pretty level to the keel.This was how I bought it.
I couldn't help but feel the outboard wasn't 'biting' into the water enough and was running quite high revs.

The bow was raising on throttle so I put some extra ballast (the wife) at the front and it did help a little. I'm 15 stone+ and with a* 25 litre fuel can at the back probably didn't help.
I tried keeping the revs low, building a bit of speed and did manage to get it on the plane a few times but will try and experiment by taking it down a notch on the trim next time.

My question is, do people tend to change the manual trim setting on a trip by trip basis, depending on load, conditions etc.. or do people leave it on a certain setting and alter their handling of the engine/craft?

Any advice would be greatly appreciated.

[rik_elliott]

Before having ptt I used to keep my trim on hole 2 out from the transom and move ballast about depending on the conditions. Much easier to send a passenger forward when at sea than to lean off the back fiddling with a pin that is a disaster should you drop it.

PTT was good on my sr4 but tbh it only really came in to its own when I moved on to bigger things.

[rik_elliott]

I should also ask if the prop is in good condition and have you checked for a spun hub?

[Jack09]

Thanks for reply.

First time I've heard of that so I've googled it and have had a quick read. Am I right in thinking the way to diagnose it is to mark the hub across the 2 parts and check after use to see if the lines have broken?

I imagine there's varying degrees of prop spin which could have an impact.

The hub feels quite solid and in good nick. The picture attached shows the prop, I can see one of the blades has been ground down and will look to replace but didn't envisage that just yet.

Is there a way to check for sure before I get it back in the water?

Thanks

[paintman]

The prop is knackered.
Replace it with one on good condition before doing anything else.
The vibration created by the imbalance resulting from the damage isn't going to do the gearbox any good either.

[Jack09]

I had one on order ready to go and might was well do the hub and prop at same time.

Could the damaged blade have anything to do with the issue in original post?

Thanks for advice. Will get it done ASAP

[Striker]

Originally Posted by Jack09

I had one on order ready to go and might was well do the hub and prop at same time.

Could the damaged blade have anything to do with the issue in original post?

Thanks for advice. Will get it done ASAP

Yes the prop will very much affect performance. It surprising how much a minor distortion /damage can cause.

Re the trim, you can alter it for the conditions but in reality once you are happy with it you will probably leave it alone.

For info trim down gets it on the plane quickly but reduces top end speed ( more hull in the water) and is best for choppy conditions as the deaper V at the bow is slicing the waves.

Trim up makes it slower to get on the plane (bow high as it’s trying to climb out of the hole) but gives a faster top speed due to less wetted area.

[Jack09]

Thanks for advice, I have an Avon Searider and the bow is very high out of water anyway.

I think I'll tinker with the settings and find what suits best

Much appreciated