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Old 31 December 2002, 12:46   #41
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Brian, In answer to your question as to why things are so much more expensive in the UK is that we pay the prices as shown. We accept it. We should question prices and try to get items cheaper elsewhere.

We saw this in the motorcycle world with the Parallel Importing of Motorcycles. Prices of "Officially Imported" motorcycles in the UK dropped about 15 per cent when the brave dealers brought in container loads of "Parallels". So as long as we pay the UK RRP's the more we will be ripped off by the manufactuirers/importers.
Bill.
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Old 02 January 2003, 17:43   #42
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Performance/Economy ... continued

I appreciate that (almost) all boats are unique, but I would be most grateful for your comments on fuel consumption, cruising speed and top speed in the following configurations:

a) 6mtr RIB + 115HP 4 stroke 20 gal tank and 4 pods
b) 6.5mtr RIB + 150HP HPDI + 40 gal tank and 4 pods+rear bench
c) 7mtr RIB + 200HP HPDI + 40gal tank and 4pods + rear bench

Which of these (if any) can be towed and safely launched by a small/medium saloon car with an 1800 engine? If "none", I shall seriously consider a boat stacking arrangement, at least until I can get a more suitable launch vehicle.

Thanks for your help!

Chris.
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Old 03 January 2003, 03:59   #43
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Chris

It all depends on the weight, the prop you want to have on the engine and the hull of the boat.
With the engines you describe average consumption should be between 0.8- 1.1 ltrs per mile.
Top speeds between with the standard props ranging from 45-55 knots I would say.
Towing the 7 mtr will be a problem in an 1800 cc saloon car. I think that you will pushing it to tow the 6 mtr.
I tow a 7 mtr boat total weight with engine and fuel (140 ltrs) 750 kgs (my boat is very light due to high tech materials used) with a Daihatsu 4Track 2.8 TDL and on uphills I need all the power I can get out of the Jeep.
Going in and out of the water you will definately need a 4-wheel drive type of car (preferably jeepish).
The weight of the boats you describe with fuel and full gear onboard may range from 700-1500kgs. It all depends as some 7 mtr RIBS may go over 1500 kgs.
In any case one needs more details I think to give the right answer.
Good luck!!
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Old 03 January 2003, 05:57   #44
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Chris

I won't even guess at the fuel consumption, as I don't have any real experience of the newer outboards (just older 2 strokes and diesels), but I don't mind going out on a limb and making a wild stab at some speed figures:

6mtr RIB + 115hp
Top speed 35-40kt
Cruising 15-25kt

6.5mtr RIB + 150hp
Top speed 40-45kt
Cruising 20-25kt

7mtr RIB + 200hp
Top speed 45-50kt
Cruising 20-30kt

Actual results will vary due to hull design, all up weight, sea state and driver ability, but I reckon these are reasonable figures. The cruising speed is a realistic average for a passage of a few hours in mixed conditions. Poor weather will really slow you down, especially in a smaller RIB. In good conditions you can cruise at top speed, so long as your wallet can take the strain.

As a rule, people (especially manufacturers and proud owmners of new boats) wildly overestimate both top speed and cruising speed.

Most of my experience has been in two RIBs:

Crompton 5.7m with 115hp outboard
(small console, 2 seats, 80 litres fuel)
Top speed 45kt
Cruising average 20kt

Ribtec 7.4m with 165hp diesel
(large console, 6 seats, 250 litre fuel)
Top speed 35kt
Cruising average 25kt


As for towing, don't even think of trying to pull anything bigger than a 6m RIB behind your car. Even that will be quite an effort, and you may need help from something more beefy to launch and recover. It is doable though with care and a bit of lateral thinking (live slipping the man in the boatyard a fiver to launch your boat with his tractor)

Hope this helps!

John
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Old 03 January 2003, 05:59   #45
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Hi occasionaly tow a 585 ribtec with a 100 with a volvo L reg volvo 440 but it is a 2.0 L It manages fine and will move the boat easily the problem comes when the slip is wet frount wheal drive with the weight on the back means very little grip and the only way is a rope. I have also seen th eboat pulled out by a golf tdi 130 break when my handbreak faild on the truck i was using. (thanks Chris) and that managed fine. Any way If I was u I would go for the storage option much less hassel and far better on you cluch. Have also moved a 7.8 Balistic around a yard with the volvo and seemes to be fine even up ramps ect though you wind for ever on the jocky as the suspension takes up.

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Old 03 January 2003, 08:10   #46
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May years ago when my money bought the boat and the car was secondary, I used to tow and launch my Ribtech 585, Yam 115 with a 1.4l ford escort. No probs the gear ratio of the car was great for recovery, even when loaded with dive gear. However the clutch was always hot!!

I think the issue is not towing the boat but stopping safely. Once the boat is moving then towing is easy with the exception of the odd hill. My little escort was a bugger to stop!! Boat just pushes you along.

Now adays my 2.4l Audi A4 Avant is crap at recovering the same boat, the wheels spin and the torque is in the wrong place for pull off performance. I think I am going to be buggered in a few weeks when my new boat arrives - 6.85 with 200 Yam. Time to sell the Audi and by another escort! Joke
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Old 03 January 2003, 14:26   #47
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The 150 and 200 Yam HPDI's will give around 1l per mile at cruising speeds (30-35kts say.). 1800 car will tow upto and around 6-6.5m but not very quickly! You will also have to pick your slipways carefully!

I run a 7.5m boat with the 200HPDI. She will do approx 50kts flat out and cruises easily at 25- 35kts at 1l per mile. I tow her with a 3L Isuzu Trooper. All up weight of the rig as it has a very heavy duty trailer with 50 galls of fuel on board is a good 2400kg which puts it beyond smaller 4x4's.

HTH,
Alan
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Old 03 January 2003, 17:55   #48
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What a great forum!

Thanks everyone for your input - it is exactly what I wanted to know. The 7mtr RIB + 200HP HPDI is certainly looking very attractive. I shall put my name down for a slot in the boat rack, as soon as I have sold my current boat ... but my wife still won't let me have a new one till next year!

I am not quite sure why the 150 and 200 should have the same fuel consumption, even if they are the same 2.5 litre block. I should have thought that the greater HP would come from slurping more fuel, or is it that at a given cruising speed, the same amount of energy is needed to drive the prop shaft, so an identical amount of fuel is needed?

If so, the 200 sounds like a superb engine, as the additional acceleration and top end should give tremendous performance, yet it appears to use the same fuel at cruising speeds, based on the info that you have kindly shared.

I am off to the Show tomorrow. Do say hello, if you see me - I am the one with the shiney head and am likely to be hanging around the RIB and outboard stands. I used to have hair but it seems to have got blown away in the Solent!

Regards,

Chris.
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Old 03 January 2003, 18:07   #49
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I tow mine with a Honda CRV (wife's)! Says it will cope with up to 1000k unbraked or 1500k braked trailer and it uses 4wd when needed.

There is a guy in Port St Mary on the IoM that launches a 5.8m Tornado with an MX 5!

There is also a slip in Peel, and that's steep - there's a story doing the rounds that Peel Lifeboat tractor has pulled out more cars in 2002, than there have been 'launches in anger'.
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Old 04 January 2003, 05:40   #50
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Quote:
Originally posted by Chris Murray
I am not quite sure why the 150 and 200 should have the same fuel consumption, even if they are the same 2.5 litre block. I should have thought that the greater HP would come from slurping more fuel, or is it that at a given cruising speed, the same amount of energy is needed to drive the prop shaft, so an identical amount of fuel is needed?
That's pretty much how it seems to work, give or take a bit. It also depends how heavy your hand is on the throttle

If you thrash either engine it will still guzzle fuel. I don't know whether the increase in top speed with the 200 would balance out the increase in fuel consumption, but at cruising speeds you should be OK.

John
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