Advice on home made ERG.

Gday, looking to knock up a ERG to get me through winter and was wanting some opinions on how best generate the resistance? Im looking at either a heavy flywheel and use some friction to slow it or use fan resistance. Ill be hacking up a old exercise bike for either and mounting it on a frame with some sprag clutches on either end to deliver the drive. 

Which one do you think would give the closest feel to pulling on the water?

Cheers.

Manitou Paddler has detailed instructions on converting a nordictrack into an erg as seen here

www.rivermiles.com/forum/YaBB.pl?num=1422556280

somewhere on Rivermiles he posted how to do it, or maybe i remember he sells a PDF for like $10 on how to do it yourself. hes made several and they get good feedback from the community.

His email is in the linked thread if you want to ask him about the conversion instructions.

This is one of those projects I always meant to get around to but never found a strong enough reason. 
Build a frame similar to the k1ergo/k1trainer, but instead of using a flywheel, stretch the budget and purchase a chain driven cycle trainer (Wahoo Kickr, Tacx Neo etc). 
Mount the cycle trainer under the ergo or out in front, put a chainring on the shaft where the flywheel would normally sit, and run a chain down to the ergo.  
The only drawback I could see was getting the inertia of the load similar to a kayak/ski, I'm not sure if there's scope to adjust these parameters in the Wahoo/Tacx software.  Another alternative would be the Stac Zero trainer, which adds weights to a normal cycling wheel to mimic inertia, then adjusts resistance using eddy currents.
The world of indoor cycle training software has exploded in the last few years, plus you've got the bonus of electronically adjustable resistance and integration of ANT+ sports sensors + power measurement on the trainer.  And it will be a lot quieter than any wind based flywheel.

Thanks, great idea. I didn't think about a cycle trainer. I rekon a fluid trainer with a flywheel attached will give the closest feel. However, the weight of the flywheel may have to be experimented with to get that running feel. My justification is kids work and moving to a place which has significantly less light and heat over winter will meaning wont get out enough to maintain my base for an event in spring. Cheers, keep the ideas coming!

Have you heard of anyone using a Concept 2 rowing erg?

I've seen a few SUP/canoe based adapters for the Concept2, but not a kayak version.   
Always been curious if the water rower flywheel/tank would provide a realistic load for kayak ergo, but given the way the cycling trainer electronics/software is progressing, I'd go that way if I was starting from scratch.

I think the cost of adapting a rower would be similar to the cost of just buying a Kayak ERG. Im going to go the flywheel attached to a fluid trainer way. Ill make a bunch of small steel plates  and add/remove them depending on how long it takes the resistance to decelerate the mass until if feels nice.  will probably have a shaft for the drive and a gear running to the resistance via a bike chain.  Reckon  it will cost 300 bucks all up.  Wont be done for a few months, but ill post up how i did it once im done with pics of super shoddy work.