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PostPosted: Thu Apr 19, 2012 10:51 am 
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RR, some newbie questions,

I have been trying to find the right ballast for soloing in the rear seat. I have tried 48 lbs once and 40 lbs once, so far the 48 felt better. I'm still trying to determine how much is needed for the best steering and general performance.

I know you once said you weight over 200 lbs and above indicated you use 55 lbs of ballast. Would 55 lbs of ballast be right for a 180 lb person? I guess what I'm asking is, does the hull design determine the ballast or the weight of the solo passenger? or both?

I sit in the back. I tried the front but it fell like I was fishtailing in a car the entire day.

One other quick question, at Hodges can a kayak be launched from the shoreline near I-15 or do you have to go to the boat ramp?

Thanks

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PostPosted: Thu Apr 19, 2012 5:19 pm 
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Location: Vega$ Baby!
Hi Baitman,

I, too, am also hoping RR will give us some input on ballast. His thread (which started a few years ago) is great. Very valuable info.

I weigh 230 and have been using two water bags for ballast, a 40 liter and a 30 liter, both filled 3/4 way = 100 lbs. (approx) which works great for me. I'd like to get away from the water bags (maybe carry them dry on board for back up) and free up the front area for storage. I've filled my drive well plug with lead (approx. 23 lbs.) and a 3" pvc pipe with lead (about 30 lbs) and want to put the pvc pipe in the front hull storage area, but am concerned it might deform the bottom of the boat. RR once said that if you move the center of gravity forward and lower, you can use less ballast. So hopefully we'll hear back from him.

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PostPosted: Thu Apr 19, 2012 10:27 pm 
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Baitman & VegasEric - It is a math problem.

Think about a teeter-totter. Equal weight the same distance away from the center, or lighter weight further away balances the weight on the other side of the teeter-totter. I took a look at my Oasis, and figured the center of the teeter-totter, which on a boat is the center-of-bouyancy (COB), appears to be about the aft end of the aft Mirage drive well. This is about 2 feet from the center of the front seat, and 2 feet from the center of the rear seat. A 200 lb person in each seat trims the boat perfectly.

I use a 5 gallon container of water for my ballast. It is placed at the front end of the cockpit, which is about 2-1/2 feet from the front seat center. Using junior high math, the 5 gal of H2O weighs about 45 pounds, and is about 2.25 times further away from the COB than the front seat, so it equals about the same as a 100 pound front passenger (45 x 2.25 = 101). This is a very rough calculation, but points out the general idea. If I increased the weight, and moved it further forward, I would better balance my 210 pounds. As it is, the 5 gallons of water just about puts the bow down on the water for me.

The weight being lower doesn't matter for fore and aft trim, but it does help stability side to side by lowering the center of gravity (COG). I don't think you should worry about deforming the boat while it is in the water. The water is providing buoyancy - or support - evenly around the hull. The hull can handle that amount of weight. Out of the water is another matter. 55 pounds at the front of the drive area should balance a 180 pound load in back pretty well, I would think. Using my earlier formula, 55 x 2.25 = 124, so about the same ballast as a 124 pound passenger. I weigh more and use less, and am pretty satisfied with it, although I am going to try a water bag up in the bow to see how much better I can get it.

Good luck to you both - Sherman

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PostPosted: Thu Apr 19, 2012 11:39 pm 
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Hey thanks for the response Sherminator, I appreciate it. Using your formula, I should be pretty good with my ballast. The Oasis is such a great boat I really want to get the most out of it.

The other day I was on the Colorado River, heading back to shore. I was using a water bag for ballast. The wind picked up, probably 20 mph, and it felt like I was on a roller coaster ride, with little control of the rudder. Finally made it back to shore and discovered the water bag had leaked and was almost empty. I hadn't even noticed over the course of a few hours that the bow was getting higher. Stupid newbie mistake I guess :mrgreen:

Anyway, thanks again! I appreciate it.

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Eric

2013 Caribbean Blue Outback


Last edited by VegasEric on Fri Apr 20, 2012 7:15 pm, edited 1 time in total.

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PostPosted: Fri Apr 20, 2012 7:49 am 
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The tetter todder was what I was kind of thinking about when I asked the question, thanks for the response Sherminator. I think I got it.

I have have lead weights and waterbags already, which I would use would depending on the launch site. In most cases moving the lead from the vehicle to the Oasis is a few steps and would be no problem. The lead is lower profile and can be placed further foward and based on what I think I'm hearing is the best solution.

The water bags can be used where the Oasis is launched at a distance from the vehicle. the weight would not not be as far forward, be higher, and require more weight.

Now, I just need to experiment with both methods to find the best weight for each senario. Thanks everyone.

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PostPosted: Fri Apr 20, 2012 10:55 am 
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Location: Escondido
Shermiator gave a great explanation! The boats have enough longitudinal stability so you don't have to get it exactly right. I tend to ballast a little on the light side for easier set up and better acceleration/speed (not by much though).

When the original post was written, the new Oasis wasn't even a pipe dream. With the redesigned hull I prefer the front for its longer cockpit length and snugger fit -- AND since the body weight is closer to the boat's CG, it requires much less ballast in the stern to bring the boat on its lines (20# is more than enough for me). From the front seat, the turn radius a bit larger but the cruise speed notably greater. It easily eliminates the problem of hydrodynamic lift and keeps a low wind profile.

As an aside: soloing with the new Oasis, both seats are more fun to sit in than a single IMO. From the back seat, it feels like you're commanding this massive, powerful freighter and have great access to the vast storage area in front of you; from the front, it feels just the opposite -- you're strapped in the cockpit of an F-4 Phantom (albeit without quite as much speed :lol: ); the mass of the boat melts away! Either way, those dual rudder controls give you great options! 8)


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PostPosted: Fri Apr 20, 2012 7:24 pm 
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Hey thanks Roadrunner! I appreciate the response. Before I got the Oasis, I spent a few months reading your posts and digesting everything. I just hope Hobie realizes they have a great salesman on this form! :lol:

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2013 Caribbean Blue Outback


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PostPosted: Fri Apr 20, 2012 10:59 pm 
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VegasEric wrote:
...they have a great salesman on this form! :lol:
You know, they say that converts are the worst kind! :mrgreen: As a by-product of creating new and better ways of having fun and enjoyment, Hobie has given many of us a new lease on health in the process. It's hard not to be enthusiastic about sharing such a gift! 8)


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PostPosted: Sat Apr 21, 2012 9:44 am 
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Location: Brick New Jersey
I got my 2011 Oasis last summer mid June and love the thing. Always went tandem with the wife, but now with a work schedule change, solo fishing wll be the majority of the time which presents new challenges. Roadrunner and other Oasis owner's have discovered that due to it's size and weight, the Oasis presents some challenges, that they have addressed successfully. I appreciate the ballast solutions proposed here for idea's also. For transporting my Kayak I bought a Thule Hullavator to lift the yak on my Ford Explorer, and I also got a rack system for my VW GTI so I can use the Hullavator on it too so it's a breeze to lift with one person. Heres a You Tube link showing the product http://www.youtube.com/watch?v=0MUU7BZfAuE .

The handle spacing is a challenge because the spacing is so far apart so I'll be mounting grip handles as suggested by others here on the Hobie forum. Thanks for sharing those ideas also.

As far as a ballast solution, I've read the plug cassette lead fill and the pvs pipe lead fill. I think, at least for me, an ideal solution exists per suggestion of some forum members. I went to my local kayak outfitter and found dry bags made in the USA by an American company called Seal Line.

My wife had been my ballast at 125 lbs. and the yak tracked fine and I'm 270 lbs. Without the wife in solo mode I need a solution to keep the bow from going too high out of the water. Seal Line makes dry bags of various capacities measured in litres. I went online, and apparently one litre of water weights about 2.2 lbs, so I need a bag to approximate the wifes weight to know that the bow will be oriented properly on the water to track properly. When the wife is on the yak, we have the dry bag for anything we need to bring with us.

Seal Line makes a 70 Litre dry bag called the Tie Down Bag. 70 litres of water weighs about 158 lbs, and a bit lessthan full at around 125-130 lbs. the perfect weight should be dialed in. I think that it should contour pretty well to the hull and it can be filled at the water and emptied. it also has straps so it can secured.

Here's a link as another option for Oasis owners that are considering soloing this versatile and very capable kayak. I hope that some of you find this helpful. http://www.ems.com/product/index.jsp?pr ... 3663094#sf

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2011 Oasis Ivory Dune


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PostPosted: Sat Apr 21, 2012 11:34 am 
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65Strad,

Thanks for the link to the water bag. The color matches my Oasis, plus it has a built in handle on the bag. Nice touch.

Thanks again.

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Eric

2013 Caribbean Blue Outback


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PostPosted: Sat Apr 21, 2012 1:39 pm 
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Hey Eric,

Heads up, this ballast solution Seal Line Tie Down dry bag has been discontinued HOWEVER, some places have a few left, usually $59-$69. for the 70L bag. By the way this bag has a profile that is described as "stackable" which is a definate win for an Oasis owner in that it is a real good fit.

I just ordered mine a few minutes ago online from Mountain Sports in Arlington Texas for $39.95! They have a few yellow ones left. If you call them, tell the guy Tim that Tom from NJ recommended them. Their phone 800 805-9139. Good luck.

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PostPosted: Sat Apr 21, 2012 3:10 pm 
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A word of warning re dry bags filled with water. I tried one in the bow of my Outback to keep the nose down a bit to avoid some of the hull slap and resulting spray the OB is well known for in headwinds and chop/swell. It was a Hobie dry bag and by the end of the day the majority of the contents were sloshing around in the hull. The dry bags are not watertight. I have since used sand in the dry bag. Using the teeter totter analogy - I wedge the dry bag right up into the nose for maximum effect, then when transporting the yak on the trolley put the sandbag on the seat right so it is right above the fulcrum for easiest transport.


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PostPosted: Sat Apr 21, 2012 4:06 pm 
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charlief, thanks for the heads up, those bags are to keep water out but keeping it in may be another story. Not sure how much weight one litre of sand is. Anyone have an idea?

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Tom

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PostPosted: Sat Apr 21, 2012 4:46 pm 
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Hey Tom,

They were already closed by the time I called them, so I just ordered one on-line.

Thanks for the heads up!

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Eric

2013 Caribbean Blue Outback


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PostPosted: Sun Apr 22, 2012 8:31 am 
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Put the salt water motor in front with the battery secured, and I would use the remote control.

http://www.islandhopperoutboards.com/ho ... ystem.html



Baitman wrote:
RR, some newbie questions,

I have been trying to find the right ballast for soloing in the rear seat. I have tried 48 lbs once and 40 lbs once, so far the 48 felt better. I'm still trying to determine how much is needed for the best steering and general performance.

I know you once said you weight over 200 lbs and above indicated you use 55 lbs of ballast. Would 55 lbs of ballast be right for a 180 lb person? I guess what I'm asking is, does the hull design determine the ballast or the weight of the solo passenger? or both?

I sit in the back. I tried the front but it fell like I was fishtailing in a car the entire day.

One other quick question, at Hodges can a kayak be launched from the shoreline near I-15 or do you have to go to the boat ramp?

Thanks

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