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pedal drive v longer yak in the bay

Questions new members commonly ask e.g. Which kayak should I buy?

Re: pedal drive v longer yak in the bay

Postby cheaterparts » 04 Feb 2020, 08:18

maverick wrote:Just go the AI and have the best of everything. :lol: :lol:


yes I forgot about an A.I. Mav with it's great in hull storage for rods - great surf crossing /surfing skills and light weight

cheap to - what the new model worth 8 K or so you can buy a few other kayaks cheaper than this

but really the A.I. probably should be compared to other boats in its class a trimaran ( sail boat ) rather than a kayak
My kayak PBs
Gummy shark 128 Cm -- Elephant fish 85 Cm -- Snapper 91 Cm -- KG Whiting 49 Cm -- Flathead 55 Cm -- Garfish 47 Cm --Long tail Tuna 86 cm -- Silver Trevally 40 Cm -- Cobia 117 Cm -- snook 53 Cm -- Couta 71 Cm -- Squid 44 hood length


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Re: pedal drive v longer yak in the bay

Postby maverick » 04 Feb 2020, 10:38

cheaterparts wrote:
maverick wrote:Just go the AI and have the best of everything. :lol: :lol:


yes I forgot about an A.I. Mav with it's great in hull storage for rods - great surf crossing /surfing skills and light weight

cheap to - what the new model worth 8 K or so you can buy a few other kayaks cheaper than this

but really the A.I. probably should be compared to other boats in its class a trimaran ( sail boat ) rather than a kayak


Well actually it does have great in hull storage, acres of it. Mine even converted to live well once, but still floated :lol:

The extra weight provides fantastic momentum in the surf and allows you to easily penetrate waves, leave one outrigger on and you can stand up to wee easily.

Perfection comes at cost. 8-)

Aha, yes I have a Compass, just to share with other people LoL.
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Re: pedal drive v longer yak in the bay

Postby laneends » 04 Feb 2020, 19:47

A paddle does more than propel a boat it helps steer and helps with balancing and bracing. When it gets bumpy hands by your side iinstead of on a paddle can be unnerving. Grinding directly into headwind is easier for most pedalling.

Pedal drive is going to add extra $1000 to price of equivalent kayak. Skinny kayaks can be a joy to paddle once mastered. Short wide once are just a chore.

Longer kayaks just make covering distances easier
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Re: pedal drive v longer yak in the bay

Postby Justo » 06 Feb 2020, 21:49

4liters wrote:the plonkers on facebook


:laughing1:
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Re: pedal drive v longer yak in the bay

Postby Stevep » 10 Feb 2020, 22:07

unfortunately the answer is in the physics
for a displacement hull ( i can't paddle fast enough to get a kayak on plane) the speed is limited by the length
the formula being hull speed = 1.34x square root of the length in feet
so for my old prowler 13 (4.1 M) the hull speed is ~4.9 knots maximum
the shorter the hull the slower the hull speed
a 5.5m stealth kayak has a hull speed of ~5.7 knots
hope that helps
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Re: pedal drive v longer yak in the bay

Postby laneends » 10 Feb 2020, 23:06

Stevep wrote:unfortunately the answer is in the physics
for a displacement hull ( i can't paddle fast enough to get a kayak on plane) the speed is limited by the length
the formula being hull speed = 1.34x square root of the length in feet
so for my old prowler 13 (4.1 M) the hull speed is ~4.9 knots maximum
the shorter the hull the slower the hull speed
a 5.5m stealth kayak has a hull speed of ~5.7 knots
hope that helps


Waterline width also has something to do with it.

My surf ski at 6.1m(20feet) I can just touch 14kmh(7.6knots) in it. Elite paddlers can do well over this. K1 sprint paddlers go over 17kmh(9.18knots) in 5.2m(18ft) boats and sustain 14kmh over 2 hour marathons. Of course these are skinny as compared to fishing kayaks.

Due to the lack of paddle bracing pedal kayaks have to be on the wider side as they rely heavily on primary stability. Skinniest is revo 16 at 70cm, compared to stealths at 60cm, Skis down to 43cm and flatwater K1s 40cm.

Pedals are better for hauling heavy loads compared to paddle in the same hull. Pedalling long distances quickly takes strength and endurance training, no skill, other than handling stability in rough conditions etc. Paddling fast over long distances , especially in faster boats, takes increasing levels of skill as well as fitness. .
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Re: pedal drive v longer yak in the bay

Postby Seasherpa » 10 Feb 2020, 23:20

laneends wrote:
Stevep wrote:unfortunately the answer is in the physics
for a displacement hull ( i can't paddle fast enough to get a kayak on plane) the speed is limited by the length
the formula being hull speed = 1.34x square root of the length in feet
so for my old prowler 13 (4.1 M) the hull speed is ~4.9 knots maximum
the shorter the hull the slower the hull speed
a 5.5m stealth kayak has a hull speed of ~5.7 knots
hope that helps


Waterline width also has something to do with it.


Moreso the wetted surface area but the waterline width and hull shape are factors of this
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Re: pedal drive v longer yak in the bay

Postby cheaterparts » 11 Feb 2020, 08:16

Stevep wrote:unfortunately the answer is in the physics
for a displacement hull ( i can't paddle fast enough to get a kayak on plane) the speed is limited by the length
the formula being hull speed = 1.34x square root of the length in feet
so for my old prowler 13 (4.1 M) the hull speed is ~4.9 knots maximum
the shorter the hull the slower the hull speed
a 5.5m stealth kayak has a hull speed of ~5.7 knots
hope that helps

laneends wrote:Waterline width also has something to do with it.

My surf ski at 6.1m(20feet) I can just touch 14kmh(7.6knots) in it. Elite paddlers can do well over this. K1 sprint paddlers go over 17kmh(9.18knots) in 5.2m(18ft) boats and sustain 14kmh over 2 hour marathons. Of course these are skinny as compared to fishing kayaks.

Due to the lack of paddle bracing pedal kayaks have to be on the wider side as they rely heavily on primary stability. Skinniest is revo 16 at 70cm, compared to stealths at 60cm, Skis down to 43cm and flatwater K1s 40cm.

Pedals are better for hauling heavy loads compared to paddle in the same hull. Pedalling long distances quickly takes strength and endurance training, no skill, other than handling stability in rough conditions etc. Paddling fast over long distances , especially in faster boats, takes increasing levels of skill as well as fitness. .


Seasherpa wrote:
Moreso the wetted surface area but the waterline width and hull shape are factors of this


What both keith and Eoin are pointing out is drag - water line length is one thing that all displacement hulls deal with drag however is what the paddler/pedaller has to deal with
first problem is wetted surface a longer kayak normally has a greater area of the boat effected by the friction of the water this adds drag
of cause a longer kayak is also narrower for the same stability as there is a longer surface in the water to hold you up
a narrower kayak along with the hull shape can reduce Residual drag

both fictional and residual drag is what the paddler has to over come to create speed
on most fishing kayaks we have poorly designed scuppers - good for draining water but not good for reducing drag
many have tranducers for there sounders in the water even using tranducer scupper that are not a drag free as a smooth hull

although this doesn't effect a pedal kayak the narrower hull for a paddle kayak being narrower around the feet area helps if you are using a good paddle stroke
as more power and of cause speed can be created from a catch closer to the centreline of the kayak

something that hasn't been mentioned is materials that a kayak is made from as most wont look this far

most plastics are quite soft and dont hold there shape that well so even if a good hull shape can have more drag than the design
harder plastics do this job better but are probably more costly to build

Fibreglass is normally lighter and stiffer than plastic and for the most part will hold its shape better and to no ones surprise that are normally quicker

carbon fibre ( the holy grail ) Carbon is quite stiff and strong so a kayak built from this material is normally lighter again than fibreglass and stiffer
and again normally quicker even as the same shape

of cause there are trade offs - plastic hulls are cheap to produce in high numbers with there moulding process and are fairly tough - fibreglass not as easy to make as plastic adding to the cost
and while tough probably hole easier if hitting rocks or other hard objects ( still fairly easy to repair ) - carbon more expensive than glass also needs to be handled nicer than plastic hulls and still repairable but harder to repair

Another material that can produce a light stiff hull and is not used that much in fishing kayaks is wood normally only used by DIYers - there are plenty of sea kayaks built with both marine ply or strip built using quite light wood species and glass covered
My kayak PBs
Gummy shark 128 Cm -- Elephant fish 85 Cm -- Snapper 91 Cm -- KG Whiting 49 Cm -- Flathead 55 Cm -- Garfish 47 Cm --Long tail Tuna 86 cm -- Silver Trevally 40 Cm -- Cobia 117 Cm -- snook 53 Cm -- Couta 71 Cm -- Squid 44 hood length


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