R23, R25, and R27 OB Stability Differences?

[kjpower]

Hello,

We’re about to make our final choice on which Ranger Tugs to buy, and all else aside we are left with the question of stability. My better half is a fan of stability, especially roll stability. You will not find them on the water in choppy seas. From what we understand, generally speaking a boat with a wider beam will be more stable than a boat with a narrow beam. As the R23, R25, and R27 all have the same 8’6” beam, but vary in LOA from 28’5” to 31’7” (engine down) is there any real difference in overall stability? Perhaps our next Ranger Tugs after this soon to be purchase will be a jump up to the R29 or R31 with the 10’ beam. But for now, I would take some solace in knowing my better half will be comfortable (highly subjective and contextual, I know) on an R27. Has any one been on different 8’6” beam Ranger Tugs, and have you noticed a stability difference between them?

Thanks so much,
KJ

 

[armor]

We bought a C28 and love everything but the roll stability in the Puget Sound…I often think about if we should have done the C30 or if it will be enough of a difference to upgrade.

 

[FWTMD]

This is a very general comment.

Are you concerned about stability at rest, or underway?

Under way, boats designed to plane will have the dynamic forces giving lift, also giving it some stability. Until you decide to slow down to manage heavy weather. At rest, is another story.

Then there is weight. And beam as you mention. The bigger the mass of the boat, the more stable it will be. The lower the center of gravity the more stable it will tend to be. The command bridges are lightly built, but its something up high. Many load up the cabin tops with all sorts of paddle boards and other gear. Keep your weight low. Ranger Tugs are designed to be light weight, to plane.

Boats designed to plane generally have ample "deadrise". That is the amount of V shape toward the stern. That gives lift, and gives stability on plane. But it has a lot of its buoyancy on the centerline. Which at rest makes it more tender to step onto the edges, or wave action in port. As compared to more flat bottoms aft, with little deadrise.

Its a tradeoff you make when going for the speed of an OB that planes. There is no solution to erase the physics of it. You cannot get the stability of a slow full displacement boat, into a boat designed to plane.

But the short answer is, the bigger you go the more stable it will tend to become.

Giving you the perfect argument for your wife as to why you really NEED a BIG boat. 🙂

A quick search showed this piece first, that may help. There are many more out there.

https://www.boatblurb.com/post/why-the- ... ed-designs

 

[S@LTD]

When we bought our C28 the R27 OB was brand new sitting in the water right next to it. My wife noticed a fair difference between the two with the keel on the C28 making it more stable. Our previous boat was a Cobalt with a 9’6” beam. We still noticed less stability by comparison to our old boat both at anchor and underway. Last summer we spent a week with a CW 30 and it is much like our old boat from a stability perspective. It was one compromise we made for other features and tow ability.

 

[tranmkp]

I can only speak on the inboard boats boats, mine being a 27. Coming from a sail background displacement is what its all about for comfort. Beam is good until its not good. The 27 does roll a little but the weight is down low. It will handle more that the skipper can.

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Dropbox

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[Jcat2010]

You mention stability, but don't specify stationary, roll, pitch or yaw as your preferences. It's all about tradeoffs...

Generally, a wide beam, flat bottom, boat would have great roll stability at rest (think barge), but if it were also short, it would pitch like crazy, so there is a desirable length to beam ratio. A boat that was really long, and really wide, with a flat bottom, would be the ultimate in stationary stability. But it would not be the best underway. Boats with over 3:1 length/beam will generally provide the best "ride".

If you want greater roll stability, go for more beam, but also commensurate length. Narrow beam, short waterline and high structure handles like a floating bleach bottle.

Once the boat is moving above 12 mph or so, dynamic forces will tend to stabilize roll, but longer is more helpful when stabilizing pitch and yaw.

If the beam is locked at 8.5, as with your choices, then the 27 has the longest waterline for that beam.. try the 23 vs the 27 and you can immediately see the difference. Try rough seas at 8 mph vs 12 and you can see the difference.

 

[DDean]

Agree that the boats are very capable and can handle more than the skipper can, but that doesn’t mean that they’re comfortable. My R27OB is the rolliest boat in the anchorage when I look around

 

[ohioan55]

Hello,

We’re about to make our final choice on which Ranger Tugs to buy, and all else aside we are left with the question of stability. My better half is a fan of stability, especially roll stability. You will not find them on the water in choppy seas. From what we understand, generally speaking a boat with a wider beam will be more stable than a boat with a narrow beam. As the R23, R25, and R27 all have the same 8’6” beam, but vary in LOA from 28’5” to 31’7” (engine down) is there any real difference in overall stability? Perhaps our next Ranger Tugs after this soon to be purchase will be a jump up to the R29 or R31 with the 10’ beam. But for now, I would take some solace in knowing my better half will be comfortable (highly subjective and contextual, I know) on an R27. Has any one been on different 8’6” beam Ranger Tugs, and have you noticed a stability difference between them?

Thanks so much,
KJ

It comes down to beam, IMHO. You can learn techniques to help manage situations where you expect roll (like wake), go to a bigger boat with more beam, consider a power cat type design, or consider a stabilization system. My 2 cents worth..