I had a 5KG for my 17ft Flyer, didn't have any issues lifting it Alderney System - Just made sure the anchor buoy was the correct size for it - I think the only way you can find out is test to see if it drags or not in different tides

 

I assume you trip the anchor Mark, the 2kg could hold well in the reef areas with lumps to grip on / into. In the softer areas , sand, sand/mud it could drag especially if wind is with tide. As above try and see.

 

Yes I always set the anchor to trip Steve. I might give the smaller one a try next time.

 

The amount of chain will have a huge influence, anchor weight alone is not enough information, also the length of rode, a 2kg anchor with 20m of 8mm chain and 6:1 of rode will hold better than a 5kg anchor with 10m of chain and 2:1 rode

 

I have about 20ft of 8mm chain and enough rope for 3 x depth.

 

Actually I think there's also about 8ft of 6mm chain on it also.

 

Modern anchors are so much better designed and hold in a variety of conditions, however if people anchor incorrectly even the best anchor will fail. Google search Fulcrum, Rona 2, Excel, sarca 2 etc. Things like bruce and cqr which are often mentioned on here really aren't up to scratch compared to modern anchors. This video provides some decent chain gauge calculators and rode lengths etc.

For super light and amazing holding power which isn't going to leave rust in your boat have a look at a 1.5kg Cooper anchor. I bought a Cooper for my a 550 pro rib and couldn't believe how it compared with the 4kg anchor I had been using, so I now have three of these for the three boats I own. On my main boat it's used as the backup anchor on shore with the main in deeper water, or as a backup system I use while away remote offshore camping. The Cooper anchor looks like a kids toy, made of plastic and weighing so little. All the people who have seen my coopers, first take the ****, then try mine and go out and buy one themselves!!!!!!... Media — Cooper Anchors Australia

 

I've had a 75.kg Danforth (years ago) - swapped it for a 4kg Roca (same chain) the difference was night and day. Now on a 22ft boat I have a 5kg Bruce which was on the boat when I bought it and a 4kg Rocna fisherman. Again the Rocna is miles better, but I keep the Bruce for anchoring in very rough ground where in case the trip doesn't work - I wouldn't too worried if I couldn't recover it.