Home made brew is cheaper that store bought. I used to have one of those beer buddy barrels and could make 27 bottles for less than $5 . Good beer too.
Afterall with panther martins $5, you get a snag and cry for an hour

Steve,
Here are the two sonar setups and my portable fishing kit

Man i am way ahead of you guys . Bought a hummingbird decades ago , late 80's , and put it in a camera dry box. Transducer is attached to a two piece 1/4 '' rod which is then attached to a small C clamp. Just bought an 8 AA battery holder and use rechargeable batteries. This is a way smaller and lighter setup than the 2 lantern battery unit they used to sell. Get 3 -4 days use . The box is like 6 x 8 x 4 inches . The box is 100% waterproof and strong enough to be stood on.Everything fits in the dry box, unit,cable,transducer and clamp rig and battery pack
Only takes mins to tighten the c clamp over the gunnel ,plug the wires in and you're in business. Take it everywhere on canoe trips through Algonquin.One troll around a lake and i know more about holes , drop offs etc than if you fished the lake for 20 yrs.Also shows fish icons < 1 lb, 1-2 lbs and >3 lbs .

Roman,
I too have been lost a few times . Though i should qualify that by saying i am single trip portaging with a canoe over my head. This limits my visibility . I have even brought a small can of spray paint so i can mark trees on old logging trails as i walk by - ie don't have to stop, drop gear and get out flagging  tape  . Also carry the park map, related topo of the area and even an aerial photo.  A gps would be nice but getting a signal through the canopy can be tough . 

I am not judging the girls as much as their troop leaders who should be old enough to know better . ie supply these girls with better emergency equipment .But black clothing in what is still bug season is a sure sign that people are not investing in proper gear in general . Shorts and short sleeved shirts? I wear pants all season and a long sleeved shirt ( soaked in permetherin ).  Use high tech under wear too tops and bottoms - $40 usd a piece . Everything i wear , bring etc is top of the line for weight and performance . Including goretex rain suit and ultralight canoe . Is it expensive ? yes . But has it been useful ? yes too . Of course for me its more imperative because i travel solo most of the time . And its certainly not easier lost as i was, with no other person along . 
Don't consider flagging tape as a survivalist item as these girls just proved . Algonquin is not a place to travel back country unprepared . We see too many tragedies as a result . 
And if you want a better ' big game' talked about - i'll post some speckle trout pics .

These two girls were 'rangers' in the girlscouts .  If sitting put is all they learned at that level  i am not impressed . I have lost the trail on the odd portage and had to work old logging roads to get to off portage lakes.And i never had a day in the boy scouts. A good item to have is flagging tape . Word is the trails were well used but no-one ever flagged the parts where the trail disappears? I have done it on a few low maintenance portages so the next guy doesn't have to waste his time . Now i see i may have saved the gov't 10's of thousands in rescue costs .All for the use of 50 cents of tape .
I carry  whistle as well but have found it not so good even on a lake . I recommend firecrackers or bear bangers . Wonder if these girls were carrying bear spray , a hatchet ?  In other words who are these polish girl scout leaders ? If they ever are questioned publicly , i am sure they will say its about money .Look at the way the girls were dressed ? Didn't notice footwear but i bet they weren't wearing a proper hiking or hunting boot . Flunky sandals may get you by on a good trail, but lose it where you have to reconnoiter in that 'dense' bush we hear about and you're asking for a twisted ankle or worse . These girls were on the verge of being criminally ill equipped to be travelling alone. And i wonder about the group at large . There must not be a single competent camping parent of a kid in that group . But someone will be asking these questions soon i'm sure and also who should be paying those rescue costs.

Scoutergriz,
I have traveled Algonquin since the mid eighties and am well aware of the terrain you describe. Even trying to get to lakes off portage routes . Lost myself a few times too. But with a map and common sense was able to find one of those old logging road you speak of . But if dog yelps can't be heard what about low flying chopper and turbo beaver ?  If the youngsters can't be trusted with a flare , is a fog horn acceptable? A signal mirror or signal fire?  The bush can be dense but also have more open areas where one would think the girls would go to. Now i realize  a  spot beacon  ( which i have carried for years) may be too pricey for this group but all worry here considered maybe a consideration for parents of future campers . But if all these options are not viable, then two young girls ought not be allowed to hike alone as they did.
There is just something not right ,in my opinion, about 2 days of aerial search, not being able to find the girls over a small area , that is if the  girls are able to respond. Having led canoe trips for a local university outing club i am aware of having novices and first timers on a canoe trip. So i kept trips short and simple and would not allow that sort departure from the group.And my youngest person would be 19 at least. Even so have not done it for many yrs and the club hardly offers any canoe trips these days due to lack of leaders.The effort and responsibility just too much. And that is the angle that i come from when hearing of these stories/tragedies. Its more of a punch in the gut vs an outpouring of sympathy .hope the girls are found soon with no significant injuries 

You don't know me from a hole in the wall. And psychopath ? You're way out of line . I'm looking to see these tragedies don't happen again . All you want to do is hand out the kleenex