Archimedes found: If the object is less dense than water (if it floats on water), it
displaces a weight ( = volume ) of water equal to the weight of the object. If the
object sinks in water, it simply displaces a volume of water equal to the
volume of the object. ( 1 liter of water weighs 1 kg )
OC 1 are designed for paddlers that weigh about ~180 lbs. The boat itself including ama/iakos weighs ~ 30 lbs.
The total weight is ~ 210 lbs. The boat will sink accordingly and float at the 'designed waterline'.
If you place more weight on the boat it will sink deeper = sinkage. The sinkage depends on the design and is different for each design.
An experienced boat designer's response:
"Weight is difficult to design for without compromise.
Example: A boat is designed for ~ 90 Kg ( boat and paddler ). In this design an added ~ 14 kg would cause 1 cm more draft, thus the entire boat would sit 1/2 inch deeper in the water.
That will probably not be too much of a performance difference, but in general terms I think that boats can only tolerate ~ 10-15kg + without performance loss.
It would be optimal to have 2-3 sizes of the same design to serve the paddlers best.
Competition kayaks and canoes have sizes for every 8-10 kg, S,M ,L ,XL (some even in SM ,ML,L,XL,XXL) as you can optimize the volume and reduce drag for that specific weight.
Some manufacturers state a boats 'preferred paddler weight' from 60-90 kg or 50-100 kg. ( 1 kg = 2.2 lbs ).
This does not make much sense:
The volume difference needed for these weights is 30-50 liters in the underwater hull and ca 60-100 liter overall boat volume . ( 1 gal = 3.784 liters )
The main problem/reason is, that most boats are hand designed. Therefor it is almost impossible to scale to certain weights.
A less weight sensitive boat is designed flatter so that the bow and stern are more in the water. That way a lighter paddler paddle won't lose the length.
For heavier paddlers rockered boats are better due to the rapid increase of volume with added weight, less wetted surface is induced that way.
For 60-70 kg paddlers the performance gain of a smaller boat would be much bigger than is the loss for bigger paddlers.
By adjusting the design this way for the middle weight paddler (70-75kg) you end up having 2 boats, a boat for flats and a big wave."
OC 1 design should be optimized for weight. To have one single design for all weights limits the performance of the athletes.
Here is my case for adjustable foot pedals:
the longer the boat, the less this matters
the taller you are/heavier you are, the more this may happen
in the flat it matters less than in the surf
it is design dependent, but all designs will have a spot where this will
definitely make a difference
3 inches/10 cm behind the sweet spot is bad in any case and can lose you up to 1 km/h average speed - this is a measured number from an existing design.
not being in the sweet spot is worst for taking off in the waves
a trim change of 2 cm/~ 1 inch bow up is definitely significant.
Paul Sloman observes:( agenda: 1. iako front; 2. iako rear; 3. insert iako in rear slot of ama and pull out by x".)First Paddle
Plus 1 inch from hull
Plus 1 inch from hull
Plus 3 inch Ama
Notes
• Canoe felt good in the flat
• Felt tippy in small canoe side swell
• Felt tippy going with swell
• Light 10 knot wind.
• Seat felt good
Second Paddle
Plus 2.5 inches from hull
Plus 2.5 inches from hull
Plus 0.75 inches from Ama
Notes
• Ama felt much lighter but under control
• Felt much faster going with bumps
• Canoe felt good going into swell
• 15 knot wind.
Third Paddle
Plus 2.5 inches from hull
Plus 2.5 inches from hull
Plus 0.75 inches from Ama
Notes
• Ama felt more controllable than previous paddle
• Canoe not tippy going into or with bumps.
• Ama not very easy to fly.
• 15 knot wind.
Fourth Paddle
Plus 1.5 inches from the hull
Plus 1.5 inches from the hull
Plus 1.5 inches from the Ama.
Notes
• Ama felt more controllable than previous paddle
• Canoe not tippy going into or with bumps.
• Tried to make canoe pearl but re-emerges with very little reduction to speed.
• Ama easier to fly.
• 20 knot wind.
Fifth Paddle (& next 10 sessions)
Plus 1.5 inches from the hull
Plus 1.5 inches from the hull
Plus 2 inches from the Ama
Notes
• Ama still felt under control
• Canoe not tippy going into or with bumps.
• Canoe felt very fast in the strongest wind so far.
• Punching into 1m (3.5 foot) wind chop canoe slices through without slapping, little reduction to speed.
• Ama easier to fly, wants to lift but only to a point.
• 25 knot wind.
First Race
15km flat water!
Plus 1.5 inches from the hull
Plus 1.5 inches from the hull
Plus 2 inches from the Ama
Notes
• Ama felt light and under control
• Canoe had a surprising amount of boat run in the flat conditions.
• Ama wants to lift but only to a point. Seems to be when I reach a speed of 10 km/hour.
• Can paddle whilst flying Ama is easier on this canoe than others.
• Boat easy to wash ride on, unfortunately is easy to wash ride off as well.
• Seat extremely comfortable in flat conditions.Additional comment: The ‘guide’ is just one paddler’s record of how he trimmed his Zephyr.
Naturally you should make your own little chart to see how your set up works for you in your specific water conditions.
You can also email Outrigger Connection and ask the designer of the boat for advice.
Following Paul Gay you should trim your ama by using a water balance and make sure that your deck is horizontal; ( measure while in flat water ).
Next to feel, you can do the following:
I count my strokes on a short segment of about 100 yards before/after almost every practice - upwind, turn around, downwind.
This gives me a general feel about the glide that I have that day. This info may convince me to keep a setting or change the rigging.
