Trim Tabs on Avon Searider 4M

[Pikey Dave]

Originally Posted by Last Tango

That would be almost as much over the top as fitting trim tabs to a 4 mtr boat.

Absolutely, hence all the (good) advice to the OP to sort out the fundamental problem rather than trying to stick a plaster on it. Personally I don't think a water ballast tank is a good solution, it isn't fast enough (imo) to react in a tricky situation & wouldn't be a substitute for PTT. They are used to give semi-permanent trim to an un-balanced setup e.g when towing skiers or casualties, you would still use the PTT to fine tune or make quick alterations e.g turning into a following sea.

[69cmw]

Originally Posted by Last Tango

A bit outside the box........but, instead of a bag of sand how about a ballast tank "ski-boat" style and some pumping arrangement to fill and empty it?

I have a dump/ballast tank in a Ring 18 speed/ski boat with a pick up and dump mechanism on it.

I have also had a Avon SR4 and I would never even think of putting anything like that in it.

The best advice is from Matt H. Mine was set up exactly the same and I had no issues with the handling. [emoji106]

[Poly]

Originally Posted by Mextli

As much as I'd love to move the fuel tank foreward, it would either cost me range(which I really can't go without) or deck space(As the console would have to move back which would involve major work, which is not an option either)

Or just a more creative fuel tank shape/storage?

[jeffstevens763@g]

Get the biggest tank that fits in your console cost around £100 carry a spare 25 ltrs in the bow if needed.
your boat is built to be in balance with the engine and console set up as it is even manual tilt will sort a level plane.
My opinion but why do you want to carry sand/ water no help to you at all if you need weight carry fuel stick your kit in dry bags stick them in the bow.
Jack your boat up on the trailer in the middle shift kit around till you achieve equilibrium trim your engine two holes up and try that.
Leave the sand on the beach

[Mextli]

Originally Posted by Poly

Or just a more creative fuel tank shape/storage?

Yep, Avon fuel bags, two of them fastened to the tubes and sitting in the joint between the tubes and the hull inside would be perfect, but I'm currently not able to afford that(I just bought Powertrim a few hours ago ) But it is on my list because it gives more deck space.

I'll see how it works out with PTT, and if that doesn't cure my problem, I will start moving fuel around. I wanted to avoid that because it would mean loosing a few comforts like a fuel gauge and a single fill tank (I'd need one under the console and one hidden away somewhere, possibly in front of the console where there isn't much space as well, the Anchor also lives up there..) but ultimately the rough-water handling is much more important(the handling isn't THAT bad, but it's still not perfect, and after all the equipment I carry around with me, I want it to be, else the time invested into that little boat would be a complete waste.)

[beamishken]

We have a stainless tank lying around that came out of my sons sr4 which should fit in front of your console. It's triangular to fit in the bow you can just see it forward of the console in the picture
We've changed his console and won't be refitting the tank if you think it may be of use to you I can take some clearer pictures for you

[Mextli]

Hey

If you could send me the dimensions and clearer pictures, once I'm home from my holidays I can tell you if it would fit.

Thanks

[jonp]

Originally Posted by matt h

You just covering up the issue, which is 40kgs of fuel/extra weight on the transom/stern, the Hulk tanks fit nicely under that consol, 22L if i remember and if you need to carry an extra fuel capacity then add a Hulk tank 12L or the 22L up front as shown.
Thus leaving your stern light as it should be especially with out PTT.
SR4 's are small slim boats and don't take kindly stacking weight up on its arse!

If you want it to handle better, your going to have to move the fuel or counteract a 40kg problem dude

My thoughts exactly, besides how often would a little boat boat like that need 45 lt. A 20 lt fuel tank brought forward and a spare 10 lt can should last quite a while. I use 33 lt on 130 km trips with a 70 hp.

Jon

[Mextli]

Originally Posted by jonp

My thoughts exactly, besides how often would a little boat boat like that need 45 lt. A 20 lt fuel tank brought forward and a spare 10 lt can should last quite a while. I use 33 lt on 130 km trips with a 70 hp.

Jon

Actually I usually empty the 40l quite fast, back when I broke my fuel tank i was thinking about a 60L replacement.
Then again im currently usin 0.5 per km so its propably the prop and motor height(which i cant raise more because of the trim issues)

[beamishken]

The 55 two stroke will drink far more than a 70 4 stroke and the range required is totally down to the users requirements so not realy for anyone else to say you have too much onboard. What's the saying "you only have too much fuel when your on fire"
Regardless of the ballance of the boat the power trim will transform the handling & ride so once the trims fitted then you can re-evaluate the ballance then
If required

[Chris Caton]

twin jockey seat/console complete with 90l fuel tank, anchor locker in the bow, Honda 50 with ptt, and a fat old bloke, works fine for me, even with my much better half aboard we can still explore the Nth Wales coastline and trips round Anglesey sip around 35l [emoji41]

[jambo]

Originally Posted by willk

That's just silly.

If it was me, I'd glass a rail into the deck and rig a pulley system to run a block of lead fore and aft. You could use a sailing winch. Not sure where I'd store the handle when not in use. It's a can of worms.

I can think of a suitable place to store the handle!![emoji23]

[Mextli]

Yep will do!

I only hope the Powertrim will be working and oil-tight. I already bought a new pump motor to go with it, now hoping i don't have to replace the seals and the pistons too.

@Chris My searider is still very much driveable even set up the way it currently is, but I'm not 100% happy about it. How does yours perform in head seas?(genuine interest here) and where do you store the fuel?

[Chris Caton]

Originally Posted by Mextli

@Chris My searider is still very much driveable even set up the way it currently is, but I'm not 100% happy about it. How does yours perform in head seas?(genuine interest here) and where do you store the fuel?

hi Luke, the fuel tank is fitted inside the console/front seat and holds around 90l. I'm more than happy with the setup, I think the weight seems to be balanced just about right and the Honda pushes it along nicely upto around 35knots, so far the rib has been fine in all conditions I've been out in, head seas don't seem to bother it, I think I'll be giving up long before the Searider does
cheers, Chris

[Mextli]

Well the 90l Fuel tank should compensate the weighty engines and the Hondas are quite light for 4 Strokes.

Perhaps I'm driving too fast. Mine goes at 38kts, but the boat gets very light and starts to chinewalk quite badly.

[matt h]

Hope that works!!.

[Chris Caton]

Originally Posted by Mextli

Well the 90l Fuel tank should compensate the weighty engines and the Hondas are quite light for 4 Strokes.

Perhaps I'm driving too fast. Mine goes at 38kts, but the boat gets very light and starts to chinewalk quite badly.

when I was looking for an engine, the Honda was the lightest 4 stroke available

I think it might go a bit faster if I changed the prop, but to be honest I'm happy with it as it is, it takes a bit of coaxing to get up on the plane with two on board, but once the flooding hull empties out it goes well enough

[Mextli]

Originally Posted by Chris Caton

I think it might go a bit faster if I changed the prop, but to be honest I'm happy with it as it is, it takes a bit of coaxing to get up on the plane with two on board, but once the flooding hull empties out it goes well enough

You know, the not-getting-on-the-plane-fast-enought COULD be remedied with a set of ... wait for it.... Trim Tabs.

[matt h]

They will make. O difference for the initial take up. Good balance is everything on a small craft as said dude. Heavy engines and a large non equilibrium positioned fuel tank will kill its performance.

[Mextli]

I wasnt serious.

But in theory they should improve the takeoff. Trim tabs (and engine trim, trim tabs are just more effective trimming down) work very well to reduce the time needed to get on the plane as well as reduce the speed needed to keep the boat there