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Old 22 March 2009, 08:27   #1
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Ribcraft 585: Stern heavy solution ?

Anyone got any long term ideas to solve the common problem of ribcraft 585 being back heavy when fully seated! It's the 585 with 140 suzuki and 4 jockey seats and its about 3 years old!

So far we have used people on the bow and bags but were looking for something more permanment! This is our plan....

create a 'secret' bow compartment infront of the current anchor locker and fill with chain and sand bags ?

Anyone got any ideas on the above plan or any ideas of there own ?

and we are determined to do it DIY (i am a boat builder though)!!!


Thanks in advanced !

i'd also like to add that it is only an issue with a full boat and lots of baggage and the problem is only getting onto the plane! on your own or 2-up with a light boat... they are an aboslute blast ! We do alot of skiing etc so the lack of planing is abit of an issue !
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Old 22 March 2009, 09:15   #2
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Fit trim tabs. The QL tabs from volvo marine are great and very easy to fit.
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Old 22 March 2009, 09:51   #3
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I looked into those breifly and had a play with some and didn't find them to useful!
the boats I were testing them with were 10m-ish, 7ish tonnes and 600+ hp! I tried a smalled boat witha trim tab and was quite supprised at the effectiveness but once the boat was outta the water, I realised the trim tab was 1m x 1m and isn't too appropriate since people climb over the transom!

Anyone know if the smaller tabs will be effictive on this kind of boat set up ?

Thanks again
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Old 22 March 2009, 09:57   #4
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The QL tabs are just as effective as normal tabs but they are far less obtrusive. They stick down vertically and auto retract after use. Less prone to damage. They also do an auto version that is like a stability control for your boat. Similar systems are used on the fast cat ferries.


http://www.qlboattrim.co.uk/

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Old 22 March 2009, 10:07   #5
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What size under deck tank have you, And do you find things get better as the fuel gets lower. I had a simillar experience with my 5.8 vipermax while running with a full tank. so started to gauge my fuel useage for what i was doing a bit better, A noticeable difference.
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Old 22 March 2009, 13:10   #6
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I have same set up.(only difference is mine is the stretched 585...now 6 meters)
Got the 180 ltr stainless tank... always near full, twin batts, big console, 2" A frame, but
I don't have a big issue 4 up. RC is a well built, heavier boat than many.

Have you checked for water in the hull? Undo the bung in the transom well and see what comes out when on your trailer with bow well up. Never found any in mine though. Suzi 140 only weighs 186 kg. Tabs will doubtless help below 4,000 rpm.
I'm running with 22" stainless suzi prop that has been balanced and 'tweaked' by Prop Solutions. (money well spent!)
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Old 22 March 2009, 13:17   #7
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Hi Will
I have the same rig as you and bass Boy only difference I have 150 mariner with fins.
Like BB I have not had any trouble and I reularly cruise the West of Scotland on full tank 40 galls and 4 up. BB's suggestion is a good one but also jhave you checked your trim mechanism?
Hope you find the cause as they are great boats in the weather/sea.
Happy ribbing.
J
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Old 22 March 2009, 13:17   #8
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Quote:
Originally Posted by codprawn View Post
Fit trim tabs. The QL tabs from volvo marine are great and very easy to fit.
Cod did you fit these to the codship or did you put them on your sib?
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Old 22 March 2009, 13:20   #9
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Second thought, what type of prop have you got on, as it may make a differnce. If in doubt about the whole issue give Ribcraft a phone I have always found them very helpful in such situations.
Cheers
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Old 22 March 2009, 13:31   #10
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As Jambo says, prop choice is key. You need to bear in mind that the gear ratio on Suzi 140 was lowered a touch in 2006/7 I think. My standard supplied 21" ali prop was pretty crap really. Hole shot wasn't bad but top end and grip was pants. Then tried 23" ali and had engine lowered 1 notch. Much better. Then tried 22" SS......what a difference! Wouldn't mind trying a 23" SS though.
I also use iridium plugs and that great Aussie fuel treatment.....'FuelSet'.
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Old 22 March 2009, 13:38   #11
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I think its probably that extra length meaning you can move the console etc that little bit further forward !

This boat, as I've said is fine with a light load but unfortunatley it is mainly used with heavy loads and want to improve the 0-plane time!

The owner of the boat seems pretty keen on doing the bow ballast thing !

Any breif ideas on prices 4 the volvo tabs above, I've fitted them but don't know there value lol!

Cheers again !
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Old 22 March 2009, 13:42   #12
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Will, the other thing re props you could if you wish quick hole shot is to fit a skiers prop like the high five or equivalent.
J
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Old 22 March 2009, 13:50   #13
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Why add MORE weight! Try out the other suggestions before trying to push more kg's through the water!!!!!
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Old 22 March 2009, 14:17   #14
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Before he adds a couple of hundred weight of concrete in the sharp end, has he checked to see if there is any water in the hull? and does he trim the engine in before hitting the go faster lever?

Pete
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Old 23 March 2009, 07:30   #15
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My Ribtect 585, 115 Merc 4 stroke is pretty similar and i have the same issue - mainly because the console is so far back.

I fited doel fins and they have made an improvement, especially when travelling slowly when it wanders round less. It planes easier, is more stable and trims out way better.

I'd defintely try tabs/fins on a similar boat, i'm sure you'll find some improvement.
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Old 23 March 2009, 07:45   #16
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In my valiant 5.20 with suzuki 70, the console is located nearer the back of the boat than the front... when the engine is trimmed right up... and you going flat out its really unstable if you do a sharp turn left to right and then right to left like that? or when i go over big waves and get air I always try and trim the engine down so it keeps the bow down! Im thinking about putting my anchor, chain + rope ina bucket in the anchor locker... dono if it will make any difference though??
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Old 23 March 2009, 07:48   #17
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Ballast tank?

Hi Will,

Once you've checked all the stuff that others have suggested - props, water trapped, fuel etc and if you decide that more weight forward is the only answer would it not be best to achieve this with a ballast tank forward. This can then be filled when needed and emptied when not. Special transom fitting and a bit of pipework and you're done. Sort of - but you're a boat builder so you know what I mean!
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Old 23 March 2009, 15:46   #18
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have 585 with 115, had same prob, just change prop/ get something bit smaller you'll lose top end but will get up faster and keep bow down.you won't believe the dif. i just switch back if going cruising with no weight
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Old 24 March 2009, 11:56   #19
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I have a stern heavy Tohatsu 6.1 with a 150 opt plus aux and a-frame. I can either do 8 knots or 16 but nothing in the middle. I'm going to give these Smart tabs a try. I'll let you know how I get on with them in 2 weeks or so.

I have tried to weight the bow and there's no water in the bilges so I think its worth a try.

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Old 24 March 2009, 15:45   #20
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Ok, cheers guys!

Gonna show the owner the ideas now and see what he thinks! I feel slightly embarrased lol, i like to think im pretty knowledgable about making boats quicker lol and all I came up with was sand ballast in the anchor locker or prop!

By the way, pretty sure there's no water in the boat! getting her weighed soon to see lol!
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