Weight distribution

[JSP]

I'm trying to find the best position for my new fuel tank by trial and error. Bit of a pain as it's a trip out every time I move it a bit (it's a real pain I says to the wife, sick of going out on that RIB trying to get this sorted ).

Went out yesterday with the centre of the tank slightly forward of where the old 2 X 25L tanks where. Had 40L in the 120L tank. In the flat calm water of the river wyre all was well. Normally I get about 40 knots with two people plus 50L of fuel and around 45 knots with just me on board, got around 43 knots yesterday, 2 people and 40 litres.
Felt like I was on the right path So set out out into Morecambe bay to see how it would handle any swell. The water was very calm but there was a hell of allot of mashed up wakes from a couple of RIBs, jet ski's etc. The ride through the was allot more uncomfortable than normal and at one point the bow semmed to stick and we where thrown violently sideways. My old man was not happy but got told to shut up as he was there for ballast lol.

So it would seem it's bow heavy, it's more obviouse by how less responsive the bow was when trimming up. I'm now going to move it back slightly, fix it down again and try it out, but that wont be until next week

So I need to tap into your experiance folks. Any tips, tricks for setting up wial on the trailer to minimise sea trials.

[PeterM]

No idea on how to set it up - but it does seem like a fantastic reason (excuse) to take the boat out more ! Good one - I'm now off to tell the wife I need to think about doing the same & will need to run with full & empty tanks in differing sea conditions - so see you in a month or so !

[JSP]

After my tanks done, engine seziour due to lack of use and a replacement engine costing £9000 will be my next ticket onto the water

[Cookee]

Fine tuning is tricky to predict - don't forget changing the prop can make an even bigger difference to the handling of a boat. How about taking out a sizeable weight and move it fore and aft to see what the results are - you will at least get a feeling for which direction to move things in.

The biggest single thing to remember is that the effect of the position of the fuel tank will diminish as you use fuel, it is better to move things that remain a constant weight such as the battery, anchor etc.

[doggypaddle]

Originally Posted by Cookee

Fine tuning is tricky to predict - don't forget changing the prop can make an even bigger difference to the handling of a boat.

Very good point, though if youre using a K series 19 or 21 it shouldnt be a problem as most of the yam/sr combination owners have found the yam K series prop pretty much the best prop for the job.

[JSP]

This going to be harder than I thought, everythings Kate moss (not much at the front). Haven't got a K serries prop, it's a SS 13x19.

Right going from the transom (weight wise), engine, Jockey seat (battery and one or two fat gits on top), console with just under half the tank under it, Other half of the tank, anchor then Sea.

I know what you mean about the fuel not being a constant weight.

[JSP]

The console on mine is further back than the original layout of a searider so I thought having the fuel tank a bit further forward would be ok.

[tim2658]

Hi john mine is the same tank as yours and in the same place as yours,if i have someone sat on the seat built over the tank then she is nose heavy but if everyone is on the jockey is rides lovely in any condition ,this weekend is the first time the tank was nearly full and she was fine

[JSP]

Originally Posted by tim2658

Hi john mine is the same tank as yours and in the same place as yours,if i have someone sat on the seat built over the tank then she is nose heavy but if everyone is on the jockey is rides lovely in any condition ,this weekend is the first time the tank was nearly full and she was fine

That's interesting to know Tim cheers. When you say nearly full, was it over 100 litres? I'm a little concerned about that amount of fuel sloshing about.

[tim2658]

well i did have about 70l in the tank plus in the front locker i had a 6kg anchor plus chain and all my gear (ie beers ) in the steering locker so a lot of weight foward, i have had a couple of 5.4's before and this is the best balanced by far and the fastest , we had one with a merc 115 with the tank at the rear under the jockey and one with a yam 85 with the two tanks at the rear..

[JSP]

Originally Posted by tim2658

well i did have about 70l in the tank plus in the front locker i had a 6kg anchor plus chain and all my gear (ie beers ) in the steering locker so a lot of weight foward, i have had a couple of 5.4's before and this is the best balanced by far and the fastest , we had one with a merc 115 with the tank at the rear under the jockey and one with a yam 85 with the two tanks at the rear..

Well I'm a little lost then. Before the bow was light and responded ok to trim but now it seemed nose heavy. Could a different prop be the answer?

I know with the current set up I can't do fast turns. Prop just looses grip. Or could that be me trimming in to much?

[tim2658]

dont know then john i must admit she wouldnt trim very well when there was someone on the front seat but if not she does lovely ,how far from the far point of the bow (inside the tube )is your tank,

[JSP]

I'm crap at guesstimating so will measure up.

[DM]

Originally Posted by JSP

Any tips, tricks for setting up

That boat will only work properly with a special yellow prop as per the pic.

These yellow props are very rare, expensive and hard to find.

[JSP]

Originally Posted by DM

That boat will only work properly with a special yellow prop as per the pic.

These yellow props are very rare, expensive and hard to find.

I wish the motor still looked that mint Dave!

John ~Off to spray his prop yellow~