Reply
 
Thread Tools Search this Thread
 
Old 05 December 2007, 05:01   #11
Member
 
havener's Avatar
 
Country: UK - England
Town: Far west!
Boat name: Vigilant
Make: Humber
Length: 6m +
Engine: 90hp
Join Date: Feb 2006
Posts: 505
Tim,

Maybe you need to know a little bit about the character offering the advice.

As you will have seen from his other posts, he knows better than the RYA, lifeboat crews, merchant mariners, etc. I'd take any tips from him with a large pinch of salt.

If its likely to upset people, I'll say no more on the subject.

Simon
__________________

__________________
havener is offline   Reply With Quote
Old 05 December 2007, 05:08   #12
Member
 
Country: UK - England
Town: Mayfair, London
Make: RibEye/Ferretti 881
Length: 7m +
Engine: Yamaha 25/Twin MTU
Join Date: Oct 2002
Posts: 690
Glancing at the Venturers website I notice he has received the MBE plus various other awards for his charity work over 40 years.

Despite some of his views on other rescue organisations, his achievements are a damned sight greater than the vast majority of other folk and as such deserves respect rather than abuse.
__________________

__________________
timw is offline   Reply With Quote
Old 05 December 2007, 05:23   #13
Member
 
Cookee's Avatar
 
Country: UK - England
Town: Salcombe, Devon, UK
Boat name: BananaShark
Make: BananaShark
Length: 10m +
Engine: 2xYanmar 260 diesels
Join Date: Mar 2003
Posts: 4,225
Quote:
Originally Posted by Tiffy View Post
At slow speed water jets tend to wander, this can be corrected by
lowering the bucket and increasing revs ; but not speed.
Or you can try as we did with our Ocean Dynamic and other smaller ribs.
by fitting a skeg similar to that used on a surf board.(even use a old one )

Turning 360 degrees in your own lengh. Put the steering wheel hard over
either way , keep steady low revs ,and juggle your bucket from neutral
up and down. This is because jet turn in the same direction in forward
and reverse.

On larger jets we advise a 1:1 gearbox, Enables better control in
Marina and tight spots without having to stop the engine. Also although
reverse gear does not give reverse motion. It enables you to back flush
plastic bags , weed ect.

Everyone does everything differently, but my opinion as a boatbuilder is that a skeg would get ripped off if you did a crash turn, or at the very least put a lot of strain on things and would hinder the turning ability of a jet.

Instead of "jiggling" forward and reverse we tend to set the bucket where it's effectively in neutral, neither forward or reverse, and increase the rpm as necessary to rotate the boat at the required speed.

I don't understand your last comment - the Mercury jet unit that comes with the 120hp isn't 1:1, but if it did it still wouldn't have a reverse! If you mean a regular marine gearbox in front of the jet that would move the engine further forward in the boat and mess up the centre of gravity if a boat had been designed not to have one, and a pointless expensive modification IMHO!

Not disagreeing with you, but would be interested if these tips are passed on from a training source or your own "Tips"?
__________________
Cookee
Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
Cookee is offline   Reply With Quote
Old 05 December 2007, 11:05   #14
Member
 
pressman's Avatar
 
Country: UK - England
Town: helston
Boat name: pressman
Make: Carson 900
Length: 9m +
Engine: twin 370 yanmar
Join Date: Jul 2005
Posts: 373
Quote:
Originally Posted by Nasher View Post
Hey Pressman good to see you back

Nasher
Cheers Nasher been a very busy year one way and another, but wont complain
__________________
pressman is offline   Reply With Quote
Old 05 December 2007, 17:17   #15
Member
 
Country: UK - Wales
Town: swansea
Boat name: Too Blue
Make: BLANK
Length: 8m +
Engine: Suzuki DT225
Join Date: Mar 2004
Posts: 12,791
Quote:
Originally Posted by timw View Post
Glancing at the Venturers website I notice he has received the MBE plus various other awards for his charity work over 40 years.

Despite some of his views on other rescue organisations, his achievements are a damned sight greater than the vast majority of other folk and as such deserves respect rather than abuse.
I seem to remember reading an article in a boat mag where the RNLI were struggling with a rescue and the Venturers came along and saved the day.........

Now this was probably due to the fact the Ocean Dynamics is a much bigger boat but Tiffy seems to do nothing but good if he possible can - surely that deserves some respect in itself???

Some people also criticised Shaun White and yet many regard him as a genius and the father of extreme ribbing - I suppose you can't please ALL of the people all of the time!!!
__________________
codprawn is offline   Reply With Quote
Old 06 December 2007, 18:13   #16
Member
 
Matt-V-SAR's Avatar
 
Country: UK - England
Town: Southampton
Boat name: Venturer Rescue One
Make: Ocean Dynamics
Length: 9m +
Engine: 400 hp Iveco NEF
Join Date: Nov 2007
Posts: 83
Quote:
my opinion as a boatbuilder is that a skeg would get ripped off if you did a crash turn

With our (the Venturers) main 9 meter we have two large skegs under the stern plate at the rear, these are (i beleive) light ally fins,

they do help stabalise the boat at slow speeds etc, and you do risk that if you do hard turns then you may bend them out, but not snap them off.

However this isnt a problem for us as we dont do sharp turns with the jet, or crash stops so when heading into harbours and up rivers, can be usefull to have.

Quote:
Instead of "jiggling" forward and reverse we tend to set the bucket where it's effectively in neutral, neither forward or reverse, and increase the rpm as necessary to rotate the boat at the required speed.
As you said everyone has thier different ways, and if they work then thats great, the reason we "Jiggle" the bucket is because we turn slowly and with jiggling the bucket we can move forward a bit, astern a bit, etc etc so we find (especially with a big boat) that we can very precisely move the boat in any direction...expecpt up and down....although that would be fun

Being able to put the bucket from wide open to fully closed in the matter of a second is nice to have, and as Tiffy already said, we have a reverse gear, but it dosnt make the boat go astern, just backflushes (usefull in the Beaulieu river when you can reguarly have a game of "Dodge the seaweed...plastic bag.." )

As for havener..

Quote:
If its likely to upset people, I'll say no more on the subject.
Very nice of you to say this, however who do you think it is likely to upset the most?

Answer being the person you are posting it about.

I am aware you dont seem to like the Venturers, or Tiff, but please dont find escuses to take stabs at him.

He is a kind guy who has done alot for alot of people,

(not taking a dig at you -just saying)

Matt
__________________
Matt

Matt-V-SAR is offline   Reply With Quote
Old 07 December 2007, 04:46   #17
Member
 
Cookee's Avatar
 
Country: UK - England
Town: Salcombe, Devon, UK
Boat name: BananaShark
Make: BananaShark
Length: 10m +
Engine: 2xYanmar 260 diesels
Join Date: Mar 2003
Posts: 4,225
Quote:
Originally Posted by Matt-V-SAR View Post
With our (the Venturers) main 9 meter we have two large skegs under the stern plate at the rear, these are (i beleive) light ally fins,

they do help stabalise the boat at slow speeds etc, and you do risk that if you do hard turns then you may bend them out, but not snap them off.

However this isnt a problem for us as we dont do sharp turns with the jet, or crash stops so when heading into harbours and up rivers, can be usefull to have.



As you said everyone has thier different ways, and if they work then thats great, the reason we "Jiggle" the bucket is because we turn slowly and with jiggling the bucket we can move forward a bit, astern a bit, etc etc so we find (especially with a big boat) that we can very precisely move the boat in any direction...expecpt up and down....although that would be fun

Being able to put the bucket from wide open to fully closed in the matter of a second is nice to have, and as Tiffy already said, we have a reverse gear, but it dosnt make the boat go astern, just backflushes (usefull in the Beaulieu river when you can reguarly have a game of "Dodge the seaweed...plastic bag.." )



Matt
As for the skegs - aluminium ones would of course bend before breaking, but epoxy or carbon windsurf ones would break or do damage.

Jiggling - yes of course you can move backwards and forwards whilst rotating, we can do that as well, but that wasn't the point of what was being said unless there was a hidden meaning?

As for reverse gear - this was given as a "tip" not a "we have" and my comments stand.

To sum up I think the comments both you and Tiff are making do not apply to most of the boating world, but rather to your unique situation, with a small amount of concentration our jet boat runs straight, doesn't need a skeg or a special expensive gearbox!

No offence intended!
__________________
Cookee
Originally Posted by Zippy
When a boat looks that good who needs tubes!!!
Cookee is offline   Reply With Quote
Old 07 December 2007, 04:54   #18
Member
 
Country: UK - Scotland
Town: Oban
Length: 5m +
Join Date: Mar 2006
Posts: 18
The company I work for builds aluminium workboats, mostly driven by jets but few RIBS.

I think waterjet handling is hard to understand if your not used to using. However from my exprience conducting sea trials with new owners they seem to be intuative to use and people pick them up very quickly.

It is true that the boat can wander a little at low speed and fins are often used to counter this a little. In an aluminium boat it is very easy to engineer a strong enough fin but i understand it being more difficulty on a fibreglass boat.

We are currently building a 8.5m aluminium foam collared rib for the offshore industry. It is a single jet but instead of fins to aid slow speed directional stability we have 'dropped' the jet such that it is in line with the bottom of the keel and therefore presents a flat vertical surface a little up the deadrise at the edge of the intake. This method has been used successfully in other single waterjet boats.

We fit gearboxes to all of our waterjet boats and I think it is a neccessity. The ability to disengage the jet is very important in a workboat that requires power for hydraulics etc. whilst not steaming. The ability to backflush is very important when operating in dirty water and off beaches/slipways etc.

Hope that's interesting!!

Caledonia
__________________
Caledonia is offline   Reply With Quote
Old 08 December 2007, 05:45   #19
Member
 
Country: UK - Wales
Town: Milford Haven
Boat name: Shearwater
Make: Ocean Dynamics
Length: 8m +
Engine: Yanmar 440HP
Join Date: Oct 2007
Posts: 19
New pilots tend to have trouble with jet boats wandering however as said earlier, with a little patience and experience control becomes natural and then the boat is ultra manoeuvrable. I wouldn't want to add anything to the underneath that might catch items and become a snagging hazard, also our smooth hull is a safer vessel to operate around wildlife, I don't like the idea of introducing fins. Just my opinion.

Enjoy using your Ocean Dynamics, they are a fantastic boat.
__________________
Anything is possible...
How bad do you want it?


www.venturejet.com

http://www.youtube.com/profile?user=VentureJet
swancvs is offline   Reply With Quote
Old 08 December 2007, 16:23   #20
Member
 
havener's Avatar
 
Country: UK - England
Town: Far west!
Boat name: Vigilant
Make: Humber
Length: 6m +
Engine: 90hp
Join Date: Feb 2006
Posts: 505
Quote:
I am aware you dont seem to like the Venturers, or Tiff, but please dont find escuses to take stabs at him.

He is a kind guy who has done alot for alot of people,

(not taking a dig at you -just saying)
Then you haven't read my previous posts properly.

I have a lot of time for, and good opinion of, (and knowledge of) Venturers as a youth training organisation.

What I object to is Venturers pretending to be a SAR team, and then slagging off the actions of declared, accredited services.

Quite simple really.
__________________

__________________
havener is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 22:06.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.