Limits of Capsizing

[Buckwheat]

How far in degrees can an R21 be heeled over before it capsizes?

 

[captain's cat]

On Naval Vessels, we conduct an "inclining experiment" by putting weights on the side of the ship to see how much it heels over. This allows the ship designer to calculate the "Righting Moment and Righting Arm" which will allow one to calculate the maximum amount of heel a vessel can take before it capsizes.

I doubt if the factory has done such a test but I'll bet the Naval Architect that went over the plans could tell you what the safe limits are. I'm sure you'll get very worried long before you get near the limits. 😱

Charlie

 

[brhodes]

Well, we have been worried - i checked to see if you also were crossing Georgia Straight on July 4th! We took some beam waves, close to six feet in short deep troughs off Point Roberts while experiencing engine difficulties. I'd say that the boat tossed over close to 45 degrees (or so it felt) but really seemed solid going up the side of the wave. The righting moment felt instantaneous, and at no point did we ship water over the side.

It really is quite a tough little boat when it needs to be!

Bruce

 

[commander bill]

I am not a Naval Design Engineer but served on several ships and submarines. Looking at the full keel design and the lower location of the heavy diesel engine in any of our Rangers I would guess we would still be upright after many other cruisers weren't. In heavy weather the feel is just different on our Rangers. I have been in many small boats that caused the "pucker facter" to increase with less severe swells.

 

[Andrew Custis]

All Ranger Tug models have passed inspections from CE Certfications and NMMA Standards. I cannot give you an exact degree.

 

[Buckwheat]

Hi Andrew,
I contacted NMMA about the Certifications and the specs that they were using and here is his reply:

"Jim-
Ranger Tugs was not Certified back then [2005], and only just recently completed this. There is not a US standard or regulation for this [roll], and the CE requirements for the EU place boats into categories based on weather conditions, but again, I do not believe they determine an exact roll measurement as you are seeking.

Sorry I could not provide further information."

Sincerely,

Robert E. Newsome
Director, Engineering Standards
National Marine Manufacturers Association
312.946.6275

FYI, Andrew: I have a 2005 R21
Apparently it was not certified in 2005. For curiousity sake, is there anyway that the roll measurement could be provided by your factory?

Regards,
Buckwheat

 

[Andrew Custis]

"If" its an EC no modifications have been made to the hull whether we were certified or not. Nothing has changed in that matter. We do not provide this type of information. Sorry.