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Old 02 May 2013, 03:18   #21
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Originally Posted by henryfreston View Post

I don't think I want anything with a long shafted engine because I am launching at a beach which is really flat. Launching a boat with a deep V hull is going to be too much of a hassle. Which is why I have decided to keep things light by buying a small shallow rib to stick my 25hp 2 stroke on. Looking mainly at the avon 3.4m to be honest.

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There's only 2" between a short and a longshaft and it's usually more transom heght than more draught. You won't even notice it.
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Old 02 May 2013, 03:23   #22
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Henry, I have a bit of a funny boat that is 3.9m and rated for 30hp. As nos says you would expect a bit more, but I doubt a chinese cheap import determined their limits by field trials or even carefully reasoned wisdom. Its more likely that whoever produced the technical file (if there is one) just used the formula in the iso standard.

With 25hp and a 3.8m boat I would expect 25knt top speed. Its unlikely you will want much more. Its unlikely that in most conditions with a shallow v that you could bear much more. I'm not sure I follow your logic on shaft length, other than fitting what you hve. Beware some 25 - 30 upgrades are only two parts but need a mechanic and some knowledge too.

However, its not inherently a bad plan, but I think you would prefer something with a console to feel you had moved up from a sib.?
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Old 02 May 2013, 03:43   #23
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I know that there is a 3.4m Avon for sale on my caravan site. With his 25hp 2 stroke he gets 30knts. Do you think this would be more suitable? I would hope I could do a little bit of waterskiing off it?!
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Old 02 May 2013, 03:48   #24
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Henry, I have a bit of a funny boat that is 3.9m and rated for 30hp. As nos says you would expect a bit more, but I doubt a chinese cheap import determined their limits by field trials or even carefully reasoned wisdom. Its more likely that whoever produced the technical file (if there is one) just used the formula in the iso standard.

With 25hp and a 3.8m boat I would expect 25knt top speed. Its unlikely you will want much more. Its unlikely that in most conditions with a shallow v that you could bear much more. I'm not sure I follow your logic on shaft length, other than fitting what you hve. Beware some 25 - 30 upgrades are only two parts but need a mechanic and some knowledge too.

However, its not inherently a bad plan, but I think you would prefer something with a console to feel you had moved up from a sib.?
It is not so much the shaft length more the depth of the hull if a searider which means you would hav to push the trailer out further. We don't have a proper 4x4 just a Nissan quashqui so reversing the trailer out isn't a possibility!

If you see what I am saying?
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Old 02 May 2013, 04:13   #25
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Originally Posted by henryfreston View Post
It is not so much the shaft length more the depth of the hull if a searider which means you would hav to push the trailer out further. We don't have a proper 4x4 just a Nissan quashqui so reversing the trailer out isn't a possibility!

If you see what I am saying?
Not at all-you need hardly any water to float an SR4 and hardly and to launch/recover one onto a roller trailer. You don't need to get the rollers submerged to launch. You don't drive ANY car into the water to launch. They fall apart with rust if you do and it plays merry hell with the electrics if they get wet.

The Avon 3.4, is it a rib or a sib?
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Old 02 May 2013, 04:22   #26
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Not at all-you need hardly any water to float an SR4 and hardly and to launch/recover one onto a roller trailer. You don't need to get the rollers submerged to launch. You don't drive ANY car into the water to launch. They fall apart with rust if you do and it plays merry hell with the electrics if they get wet.

The Avon 3.4, is it a rib or a sib?
The avon 3.4 is a Rib. It is just if I buy a searider I have to buy a whole new setup :/ all j have to replace is the boat and not the trailer or the engine.
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Old 02 May 2013, 05:45   #27
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Quote:
Originally Posted by henryfreston View Post
It is not so much the shaft length more the depth of the hull if a searider which means you would hav to push the trailer out further. We don't have a proper 4x4 just a Nissan quashqui so reversing the trailer out isn't a possibility!

If you see what I am saying?
If it really needs to go deeper:

(1) For launch you can usually "walk" it out with a small boat/trailer.
(2) For recovery you can use a rope.
(3) If it is regular enough to be a pain (e.g. your normal launch) then consider an extension bar on the trailer tongue. There are commercial versions but a scaffolding bar, hitch and ball can be bodged up for very little.

If the trailer has rollers you can get away with surprisingly little water. If it has bunks you will need a bit more, but I have a 2wd family car and launch a longshaft transom (3.9m) with nothing more that a rope without my back wheels or any other part of the car touching the water. I use a rope quite a bit for recovery but can usually get the boat OFF the trailer (on bunks at the moment) without unhitching the trailer.
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Old 02 May 2013, 05:59   #28
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Quote:
Originally Posted by Poly View Post

If it really needs to go deeper:

(1) For launch you can usually "walk" it out with a small boat/trailer.
(2) For recovery you can use a rope.
(3) If it is regular enough to be a pain (e.g. your normal launch) then consider an extension bar on the trailer tongue. There are commercial versions but a scaffolding bar, hitch and ball can be bodged up for very little.

If the trailer has rollers you can get away with surprisingly little water. If it has bunks you will need a bit more, but I have a 2wd family car and launch a longshaft transom (3.9m) with nothing more that a rope without my back wheels or any other part of the car touching the water. I use a rope quite a bit for recovery but can usually get the boat OFF the trailer (on bunks at the moment) without unhitching the trailer.
My trailer already has an extension basically I just don't want the hassle of selling my whole setup then buying a new one to find the engine or trailer has under lying problems :/ the reason I want a small rib is because the hull in my aluminium deck fill with water and rubbish as well as more flex in the hull resting in cavitation. I also think a little 3.4m rib will be brilliant fun!
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