Targa 40 fuel capacity

[ELJAY]

I am considering doing the long trip from Palma - Mahon - Sardinia next year - the main leg is about 200nm. Thats a good 10 hours of cruising which according to what I can find out I should be able to complete on a tank of fuel (197 gallon) assuming 1.5 mile/gallon - that said it is way too close for comfort as there are no fuelling options en route - just lots of water! Does anyone know the increase in range by dropping down to displacement speed c12kn and whether this is even practical in a full planing boat like the T40?
The other option is to go via Barcelona, Marseille etc but that is more than double the distance.

 

[petem]

What engines do you have?

@bluetooth

 

[ELJAY]

KAD300A

 

[vas]

displacement in a 40ft boat is definitely NOT 12kn.
drop to 7 and you could probably go there and back (or die of boredom )

 

[sap_2000]

1,5 nm/g or 3,02 l/nm sounds a bit optimistic for planing speeds on a heavily loaded T40 with KAD´s. Recon with around 3,5 l/nm so u have a bit of extra margin.

Given you have 197 UKG = 900 liter total and want a 20% reserve = 750 liters to play with: 200 nm x 3,5 l/nm = 700 liters used and you will have around 200 liters left in the tanks.

If you want a bigger margin then i would start the trip and do the first 4-8 hours at displacement speed around 6,5-7 knots (not 8 - 10 or 12).
At 6,5 knots your boat will drink around 1,2 l/nm or do about 4nm/ gallon.

I would cast off in the dark and do some hours at D-speed. When sunlight comes, recheck the weather forecast and then decide to press on at 25 knots or head back. This method has been used by many going from from west coast of Norway to Shetland (170-200 nm) with boats with borderline range at planning speeds.

 

[Freebee]

have you any room to place some temporary fuel filled bladders to increase your margin of safety !!

 

[Portofino]

My KAD 300 s in a Sunseeker Porto 35 , I used to burn under 80 L hr @26/27 knots 3100 / 3200 rpm
Your Targa slightly larger should very similar there about .
So 7-8 hrs to cover the 200 miles call it 600 L . Leaving 150 L ( cap 745 )

As sap-2000 says get up and set before first light .This is to give more contingency daylight time should help be needed .

 

[SC35]

Your economical displacement speed will be more like 6kts, not 12kts.

 

[jrudge]

I have done that trip. I have fuel consumption monitoring.

You need to know the fuel burn of your boat ( full tank / full tank ) and have a clean hull. Bear in mind rough weather dramatically increases consumption.

I used l to have a t40. I also looked at this trip in it and bladder tanks. This is totally impractical for a host of reasons - weight of fuel and inability to secure being the biggest issue.

The only way to stretch range is an early start and displacement speed.

I will also likely do this trip again this summer. It is a long way and there are not many boats or even ships about and you need to choose your weather window carefully.

 

[bluetooth]

I've done a recent thread on here for a trip next year. With KAD300 at 1000 revs I reckon you can more than 2.5x increase your cruising range but at a 5x factor of time. I'm doing for different reasons of not being in a rush.

 

[BruceK]

Its not so straight forward I am afraid. I recently have taken to displacement speeds and autohelm for much of my cruising and working on a miles per gallon point of view huge differences can be gained or lost according to seastate, wind and or currents while maintaining circa 1k rpm 6knts or 3krpm 18 knts as to which actually got best mpg.
I will caveat that my choice of speed has little to do with mpg and is just a empirical observation. What I can say is displacement speed done correctly, look at your following wake, will genealky give better mpg but not exactly as much as youd like to believe. I.e. I would be extremely cautious on doing any journey at displacement that I could not do on the plane. If the elements go against you you are in for some anxious momoments. imho

 

[bluetooth]

Its not so straight forward I am afraid. I recently have taken to displacement speeds and autohelm for much of my cruising and working on a miles per gallon point of view huge differences can be gained or lost according to seastate, wind and or currents while maintaining circa 1k rpm 6knts or 3krpm 18 knts as to which actually got best mpg.
I will caveat that my choice of speed has little to do with mpg and is just a empirical observation. What I can say is displacement speed done correctly, look at your following wake, will genealky give better mpg but not exactly as much as youd like to believe. I.e. I would be extremely cautious on doing any journey at displacement that I could not do on the plane. If the elements go against you you are in for some anxious momoments. imho

My caveat would that I would be doing my trip planned as a sailing boat and go with tides as I will have no deadlines. Obviously if I need to plane then I can especially when in Isles of Scilly. I would also plane to occasionally stretch the engines legs.

 

[petem]

I used l to have a t40. I also looked at this trip in it and bladder tanks. This is totally impractical for a host of reasons - weight of fuel and inability to secure being the biggest issue.

I've been pondering this. In perfect conditions, the boat should be able to make the trip at cruising speed with the 750l tank so we're talking about having some fuel in reserve.

The T40 has a 300l water tank which of course could be empty for such a crossing.

The fuel tank it 750l so you'd really need to carry an additional 20% or 150l for safety. Surely this could be done using 6x 25 litre jerry cans stowed between the single berths in the aft cabin?

Pete

 

[jrudge]

it of course depends on how much fuel you want to take. The main issue is the practicality and safety of sorting it and then getting it into the tanks.

I looked at bladder tanks and that is a non starter.

To transfer file form a can at sea in anything other than total flat calm seas I think would be difficult and hazardous.

A 25l can is heavy ( 25kg plus the can ). Going on deck 6 times to tilt and try and get the fuel in given you have nil choice on the matter as if you don't do it you can't reach your destination.

Each to their own but to me this comes under the most unwise category. .

You could of course try to pump it. I don't see this being that practical either.

The cost and risk of this compared to doing displacement cruising for as long as it takes does not seem worthwhile.

The trip is a long way

 

[petem]

it of course depends on how much fuel you want to take. The main issue is the practicality and safety of sorting it and then getting it into the tanks.

I looked at bladder tanks and that is a non starter.

To transfer file form a can at sea in anything other than total flat calm seas I think would be difficult and hazardous.

A 25l can is heavy ( 25kg plus the can ). Going on deck 6 times to tilt and try and get the fuel in given you have nil choice on the matter as if you don't do it you can't reach your destination.

Each to their own but to me this comes under the most unwise category. .

You could of course try to pump it. I don't see this being that practical either.

The cost and risk of this compared to doing displacement cruising for as long as it takes does not seem worthwhile.

The trip is a long way

To be honest, even without the fuel challenges it would be too much of an ordeal for me. And these boats are getting on now so reliability could be a factor.