Opinions on Jet Drives

[Solent-Salted]

Right then Ribmen and Ribettes,

Investigating propulsion systems and would like to know what you all believe is the best
Value For Money Jet Drives that can be powered in a dual operation set up by independent 250bhp inboards.

Want to know about ALL drives, not just the well known.

Ta.

[chewy]

Why a jet drive?

[Solent-Salted]

Well,

I am on a fact finding mission really.
Will be using diesel inboards, so a stern drive or jet system are the only two main items to be used (am happy to be corrected on that).
Jet drives are by far the more expensive method of propulsion but have the benefits of being able to work shallow, give greater manoeuvrability and have no prop directly in the water.

Actually, would like to have it expanded to include the same question for Stern Drives.

[chewy]

What about surface drives, I was going to use a jet drive on my other boat but am looking at surface drives now.
What is the boat going to be used for? Rescue work?

[Solent-Salted]

Originally Posted by chewy

What about surface drives, I was going to use a jet drive on my other boat but am looking at surface drives now.
What is the boat going to be used for? Rescue work?

Aye,

The drive system also has implications regarding coding, as you can imagine so, need to think of factoring that in too.

Have spent a number of evenings going over the spec'n and we are looking at category B.

[chewy]

Originally Posted by Solent-Salted

Aye,

The drive system also has implications regarding coding, as you can imagine so, need to think of factoring that in too.

Have spent a number of evenings going over the spec'n and we are looking at category B.

How does it affect coding?

[Solent-Salted]

The coding has certain items that refer to some drive systems.

Nothing major, more aimed at prop guards so would be stern and surface(?) drives.

[chewy]

Have you got a link to that?

Inshore Lifeboats don't run prop guards.

[Solent-Salted]

Do you want a copy of the code?

At some points its rather vague.

Prop guards are required when working in very shallow water, but I think that is more aimed at Category C & D.

The entire code refers to every single aspect of a rescue boat organisation.

[chewy]

Originally Posted by Solent-Salted

Do you want a copy of the code?

At some points its rather vague.

Prop guards are required when working in very shallow water, but I think that is more aimed at Category C & D.

The entire code refers to every single aspect of a rescue boat organisation.

So what do ILB's fall under?

[Solent-Salted]

My understanding is the Atlantics 75/85 fall under B

D Class fall under C/D?

This is still all draft though, but if it come in, any new boat built within 5 years of the implementation date must meet the specification.

There is a lot of "should" or "could" statements, very sparce on the "Must".

[chewy]

Originally Posted by Solent-Salted

My understanding is the Atlantics 75/85 fall under B

D Class fall under C/D?

This is still all draft though, but if it come in, any new boat built within 5 years of the implementation date must meet the specification.

There is a lot of "should" or "could" statements, very sparce on the "Must".

Is there a copy online?

[Solent-Salted]

Not that I know of,

I'm sure there is one somewhere.

Got mine from the MCGA.

I can ping you a copy of it.

[chewy]

I had a copy of an old one which sounds similar but it wasn't rescue specific?

[Solent-Salted]

This was last updated start of 2009 i think and is entitled

"THE CODE OF PRACTICE FOR OPEN RESCUE BOATS (< 15m)"

Real edge of your seat readin'

[Andre]

Originally Posted by Solent-Salted

Right then Ribmen and Ribettes,

Investigating propulsion systems and would like to know what you all believe is the best
Value For Money Jet Drives that can be powered in a dual operation set up by independent 250bhp inboards.

Want to know about ALL drives, not just the well known.

Ta.

Jet drives will be always more expensive then stern drives especially if you also require a gearbox.

we have fitted many twin diesel jet drives (QSD 4.2 270 + ZF gearbox + HJ 241)
Both alternatives are good but final choice will depend on requirement / application. For SAR the preference is jets and for speed for sure stern drives

[m chappelow]

Originally Posted by Solent-Salted

My understanding is the Atlantics 75/85 fall under B

D Class fall under C/D?

looking at the old code of practise 2004 part operational catagary limits . B is 4 metres high waves , C is waves up to 2 meters high and D is up to 0.5 meters high or have i misread it ,doesent seem a lot to say most D class launches will be in conditions more than that

[Solent-Salted]

It's a bit confuddlin'

Respectively, straight from the coding

Operational Limit Category: A B C D
Significant wave height maximum (m) 7 4 2 0.3
Beaufort wind force maximum 10 8 6 4

So,

We have:
Castoldis,
Hamiltons,
what others? got a brief summary for each?

[Poly]

Originally Posted by Solent-Salted

Not that I know of,

I'm sure there is one somewhere.

Got mine from the MCGA.

I can ping you a copy of it.

Not sure if this is the most up to date? http://www.mcga.gov.uk/c4mca/rescue_....02.08_1-4.pdf

Beacuse that doesn't say prop guards must be fitted at all. It says should be fitted where the circumstances (risk assement) require it, and specifically in shallow water (which from where else they use that phrase I assume they mean beach lifeguard type work)

[Solent-Salted]

Aye,

That's what I was assuming re prop guards, for C - D

And even then its "should" rather than "must".

I have been paying more attention to Jet Drives rather than props.