turdle

Also the 250 explorer is only rated to 5hp, so you would have to sell your 6hp and get a new motor as well. Just sounds like so much trouble to sell everything you have to downgrade to a smaller, less capable boat, just to go a little bit faster. 

As you can see in the picture below. ITS TINY!. The bare boat with nothing in it will only do 11 knots with one person. Add fishing gear, fuel tank, electric motor, battery etc. and you will probably max out at 8 knots.

These boats are designed for getting your from your mooring to the shore in protected water, or for fishing small creek and estuaries. Even the broadwater on a moderately windy day, would be dangerous in this boat. If you even tried venturing into the seaway the VMR would likely come and tell you off and tow you out of there. The more likely scenario would be getting swamped by a passing pleasure cruiser and sinking as soon as you leave the 6 knot zone in the broadwater.

8 hours ago, Mylesfisher said:

I’ve seen people on kayaks go to the seaway

Kayaks are very different to a Tinny. You can paddle a kayak out through the breaking surf no worries. You would be stupid to take any tinny through breaking surf. A kayak wont take on water and capsize. If a tinny takes on any water you will be very unstable, and have a good chance of capsizing. All it takes is one wave that catches you off guard, and you're in a lot of trouble.

You say that this 2.5m tinny has a great casting deck. That's all good to have a casting deck, but is it actually usable? I'd imagine standing anywhere but the middle of a 2.5m tinny would be very unstable, and not comfortable to fish from. The casting deck raises your centre of gravity, and on such a small craft, that is a terrible idea. That's probably why its for sale, it's useless. Add an electric bow mount motor and battery like you're planning and it would be even more unstable. Also if you don't have a RMDL you are limited to 6hp, which wont move you at any great speed. If you cannot start your motor for any reason while in the seaway, and the tide is running out, you're rooted. If you don't have comprehensive insurance on it, you risking losing your boat, and all your gear by taking the risk of fishing beyond your boats (and your) limits. Worst case you're risking your life!

Why trade your 3.5m tinny in for a smaller less capable boat? You won't be able to fish with your mates in a 2.5m tinny, you'll have to fish solo. Stick with your current boat. Stick with your 6hp motor. Don't worry about fishing the seaway for bigger fish at the moment, hone your skills on smaller fish in safer waters. Use the fishing tackle you already have and just enjoy fishing. Save your money, and in a couple of years you should have enough for a bigger motor on your 3.5m and add an electric motor then. 

There is plenty of great places to explore around the broardwater, canals, and rivers with your current boat and gear. Instead of trying to target jewies, mackerel and kingies, why not focus on jacks, and big lizards? 

Save your $, stick with what you already have, enjoy fishing and look at upgrading your boat/gear in a couple of years when you have your RMDL.

If its a traditional transducer without side scan, then it's shooting out a cone shaped signal, and the size of the cone depends on the frequency that you're running. As you can see in the image below, the depth displayed is never the actual depth below the boat, but the shortest distance between the transducer and the first return signal.

You will never get the transducer installed exactly plumb as the pitch of the hull varies depending on the boat speed, and roll changes depending on how the boat is loaded on the day. You're over thinking it. Just install the transducer pointing down when the boat is on the trailer. As long as its not out by 5 degrees or more, you are going to get decent readings. 

Port of Brisbane is responsible for the dredging of shipping channels in Moreton bay, as well as the stretch of river up to Breakfast Ck. Upstream of breakfast creek is MSQ's jurisdiction, and due to the depth of the river, and the type of vessels that travel upstream, all they do is maintain the navigation aids to allow for safe passage along the naturally changing channels.

The authorities could dredge the river to 100m deep, and the exact same flooding would still occur. The water is tidal, so making it deeper will not allow more outflow flow volumes. 

Wivenhoe dam is what's used for mitigation, and it did a great job this last week saving Brisbane from catastrophic events. Just last week SEQ water put out an alert that forecast modelling predicted 100-200mm of rain in the upper catchments, so planned to release large volumes of water from Somerset into Wivenhoe (less than 60% capacity at the time) and estimated the water level of Wivenhoe to increase by about 0.5m. Then the heavens opened and some of the heaviest rain ever recorded fell for 3 days straight and the dam level went up

• 25th - 80%
• 26th - 142%
• 27th - 184%

Up until the night of the 27th, they had not opened the floodgates on the dam, and the Lowood river gauge (brisbane river, not far downstream from dam wall) had hit its first peak just from inflow from other nearby catchments - see image attached.

If the dam was not there, the flooding would have been much much worse.
If they had opened the dam gates earlier, the flooding would have been quite a bit worse.
If they kept the dam closed, and it didn't breach the fused flood gates, the flooding would have been marginally better than what occurred. 
If they kept the dam closed and the flood fuses opened the gates, flooding would have been a lot worse
If the flood gate fuses failed and the entire wall failed, a lot of Brisbane would not exist today.

Flooding is a part of living in Brisbane. If you want to live close to the river and in low lying areas, you need to make sure your house is above the flood level, and you have suitable insurance.

Another image attached showing the extent of the Brisbane river catchment, and flood plains. That's a lot of area directing water into a rather narrow Brisbane river.

Anyone near the seaway/wavebreak tonight?  The tide gauges are showing a ~1m fluctuation in water levels from the tsunami. I bet the fish are a little confused at the moment.

https://apps.des.qld.gov.au/waves/graphs/gcseaway_tide.png