Kayak on roof fuel economy question

Does anyone know just how much a kayak on a car roof affects fuel economy?
My povo spec van doesn’t have a trip computer, so looking for some real world experience.
It won’t go in the van without removing the passenger seat, which is inconvenient.
I’m planning on taking it on a 500 mile round trip, with a lot of motorway driving.

for a one off trip does it really matter? Do you have any other options? Stick it on the top – stomach the extra tenner it might cost you in fuel and stop worrying.

Aero bars on my roof and the kayak upside down has virtually no effect on fuel economy in my car. I guess its down to the aerodynamics of the roofbars and the kayak.

Depends which way its on the roof 😯

Depends on if it’s a spud or double sea kayak…

Our two open canoes, side by side, can knock 5-10npg off the Galaxy – however if I slide them back, noses in slightly, it is a couple of mpg less on a long run of motorway speeds…

Always if you have a choice, inside..

Tend to drive slower with them on top, ours are 15ft tourers. Plus the kit in the back, bikes, tents, etc. Average is about 39mpg unloaded. With boats etc could be as low as 32mpg. Just think of the smiles

As matt says, depends. On all sorts of things from what sort of kayak (I’m assuming it’s something short based on description) to how you mount it and how fast you go. I’ve never really taken proper records – though with my surfski on which is long and pointy and quite aero, if I drop my speed by ~5mph I get similar economy. ISTR when we took a trip across Germany at “autobahn speeds” with a roof full of short stubby polo kayaks that the economy was quite bad though!

Are you sure you can’t get it inside without removing the seat? I used to carry windsurfers inside my car by fully reclining the passenger seat – I also put it as far forwards as possible and removed the headrest so it would recline in front of the rear seats.

Are you sure you can’t get it inside without removing the seat? I used to carry windsurfers inside my car by fully reclining the passenger seat – I also put it as far forwards as possible and removed the headrest so it would recline in front of the rear seats.

+1 my wife and I used to be able to get us and two boats in a polo. Admittedly and I3 and a Disco which were both small play boats but it was possible. Used to get my creek boat (Java) in a Clio no issue.

When we did long trips we used to estimate somewhere around 10% for motoroway driving. But that was an empty car compared to a car with 3 people and kit inside and 3 boats on the roof.

With a cockpit cover on and inverted top down rear forward then it’s probably 10% on a van. Depending how high off the roof your rack is. The rack probably accounts for as much as the boat.

Cockpit cover makes a big difference. So does tanking it at 90, and so does the engine.

My focus 1.6 diesel did about 37 with boats and 45 ish without. Previous Astra 1.9 diesel 40ish with 47ish without. Current Audi 2.0 diesel around 45 with 55 without. So around 20% on my cars.

^^ Haha, nice use of the Yaris.

Are you sure you can’t get it inside without removing the seat? I used to carry windsurfers inside my car by fully reclining the passenger seat – I also put it as far forwards as possible and removed the headrest so it would recline in front of the rear seats.

I’ll be taking a passenger, so not an option.
It’s a sit on, so quite aerodynamic. It will be going on the roof no matter what, just interested in how much it will affect things. It does make some odd howling noises at 70mph.

How many we talking?

Leave the spray deck on or fit cockpit cover.
Try reversing which way it ‘faces’.

20% extra fuel used by us with 2 kayaks on the roof going to Scotland from the English Midlands. All motorway, at 65-75mph. Albeit this was an 1100 engine, so would be working harder.

Not my car, but I own one of these boats:

I understand this knackered the fuel economy a bit – I think about 10% worse with those boats on my big estate car when we took them up to Scotland.

1 kayak not much difference but speed is lower with boat on roof – typical motorway speed 80, boat on roof – 65

All I’ve noticed is that kayaks on the roof affect the fuel economy less than bikes do.

Indeed, boats are better than bikes.
Size of engine is important – our Galaxy is waaaay better with the 2.0 /140 tdci engine than a friends smax with 1.8 tdci engine on mpg, and even more so with boats or bikes onboard.