TIG Integrity — Transom Mounted Transducer Setup Guide [ summary version]

Every principle you need to get a clean read at speed

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QUICK REFERENCE — 6 Principles at a Glance

1. Get as close to the keel as possible — cleanest, most stable water flow
2. Know where your strakes are — position between them, never behind them
3. Don't trust your welded transom plate — verify it against all principles
4. Your transom plate design could be working against you — gap and height matter
5. Transducer height — skim first, go lower if needed
6. Transducer angle — parallel to the water at chosen speed

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BEFORE YOU START — Which Side of the Boat?

	Detail
✅ Starboard is preferred	With a clockwise-spinning prop, wash travels away from the starboard transducer zone
✅ Port is fine too	Hundreds of boats run port-side with zero issues
💡 Why prop wash isn't the real concern	The boat moves forward faster than any disturbance can travel toward the transducer
⚠️ EM fields	Generated at the powerhead (top of motor) — the lower unit has negligible EM output

⚠️ HINT: Never cable-tie other cables (lights, pumps, other transducers) to your transducer cable — run it separately to avoid picking up EM interference.

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PRINCIPLE 1 — Get as Close to the Keel as Possible

	Detail
✅ Do this	Mount as close to the keel as possible — it's the lowest point with the cleanest, most stable water flow
💡 Why	As the hull lifts onto the plane, a transducer mounted wide can break the surface and lose contact entirely
⚠️ Watch out for	Transducer must sit outside the prop diameter — visualise the full trim range to confirm clearance

⚠️ ATTENTION: Check motor at full turned lock in both directions across the full trim range — confirm the outboard cannot contact the transducer at any point.

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PRINCIPLE 2 — Know Where Your Strakes Are

	Detail
✅ Do this	Position the transducer between strakes, on the flat section of the hull
💡 Why	Strakes tear up the water surface — a transducer sitting in that aerated stream cannot produce a clean image
⚠️ Watch out for	Inlets, outlets, and thru-hull fittings upstream and inline — even a slight protrusion creates a turbulence trail

Aluminium pressed hull owners — read this:

• Pressed strakes run at close intervals and aerate the entire water surface layer
• Your transducer may need to run deeper than on a plate boat
• Transducer shape matters — a large 1KW brick-style transducer is a significant challenge on a pressed hull vs. a slim Garmin GT or Lowrance 3-in-1

💡 HINT: The weld bead where the hull meets the transom can cause aeration. Sand it smooth (100–180 grit, finish with 400 grit + lubrication) in the transducer zone — but leave enough material to keep the join structurally sound.

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PRINCIPLE 3 — Don't Trust Your Welded Transom Plate

	Detail
✅ Do this	Apply all principles to your welded plate — don't assume it's correct because it's permanent
💡 Why	The fabricator knew how to weld, not necessarily where to place a transducer for speed reading
⚠️ Watch out for	Older plates designed for older transducers — reading at speed wasn't a priority when many were installed

Ask yourself:

• Is it as close to the keel as possible?
• Is it clear of strake turbulence?
• Is it clear of prop wash?
• Is it safe through the full trim and lock range?

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PRINCIPLE 4 — Your Transom Plate Design Could Be Working Against You

	Detail
✅ Ideal setup	No transom plate — transducer mounted directly against the transom
💡 Why gap matters	Every millimetre away from the transom introduces disturbed water and degrades the sonar image
⚠️ Watch out for: height	Angled folds at the lower edge of a plate raise the mounting surface — the transducer can't get low enough, and forcing it deeper exposes the fixing section of the mount to fast water, creating its own turbulence

💡 TIG Integrity mounts are designed to compensate for both gap distance and high transom plate positioning.

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PRINCIPLE 5 — Transducer Height

	Detail
✅ Starting point	Run a straight edge along the hull bottom — position the transducer so its face sits approximately halfway through its own thickness below that line
💡 Which side to measure from	Starboard transducer → measure from starboard side of transducer. Port transducer → reverse. The most water-exposed side is your reference
⚠️ Skimming caveat	A transducer perfectly placed at rest can lift clear of the water once the hull planes

When skimming doesn't work — go lower:

• Deeper keeps the transducer in contact through the hull's lifting motion
• Most people hit a wall here — they've run out of adjustment on the factory mount
• That's an equipment limitation, not a technique problem

⚠️ MAJOR POINT: A very common mistake seen in customer photos — the lower corner of the rear fixing plate, or the radiused rear section of the footprint plate, sitting below the hull line in fast water. This causes turbulence 100% of the time. No part of the mount should be below the hull line except the transducer itself.

💡 TIG Integrity mounts have longer arms specifically so you can go deeper without the rear plate digging into fast water.

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PRINCIPLE 6 — Transducer Angle

	Detail
✅ The goal	Transducer face parallel to the water at your chosen reading speed
💡 How to set it at home	Record your boat's running angle at speed with an angle finder → recreate that angle at home (jockey wheel + jack) → level the transducer with a spirit level
⚠️ No angle finder?	Search YouTube: "how to level your transducer with a level and coins" — but note these videos set it at rest, not at speed. An angle finder is more accurate and less messy

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FIND YOUR BASE ANGLE (Critical)

Your boat is never at a fixed angle — speed, trim, wind, chop, and load all shift it constantly. Every hull is different: some ride bow-high, others push the nose down under load or at certain speeds. There is no universal correct angle.

What you need is a base angle — a consistent reference point chosen from:

• Your boat's typical running behaviour
• Your chosen fishing/reading speed
• Your average water conditions

Once established, adjust your transducer angle from that baseline. Think of it as dialling in for your most common scenario, not every possible one.

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FINAL CHECKLIST — Have You Covered Everything?

• ☐ Transducer positioned as close to the keel as possible
• ☐ Clear of all strakes and inline obstructions
• ☐ Transom plate position verified against all principles
• ☐ Transom plate design assessed — gap and height considered
• ☐ Height set and tested at speed — no part of the mount below hull line
• ☐ Angle dialled in at fishing speed, not at rest
• ☐ Base angle established from your typical conditions
• ☐ Transducer cable run separately from all other cables

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STILL NOT GETTING RESULTS?

You've worked through every principle. If results are still unsatisfactory, there is only one place left to go — deeper.

Below the surface turbulence, below the aeration, below the hull disturbance — the water is stable and perfect for sonar. The problem is getting there with a factory mount, which has a fixed adjustment range and wasn't built for the pressure and drag of real fishing speeds.

This is the gap TIG Integrity products were built to fill — deeper, closer to the transom, held firmly at speed.

Transducer Brand	Compatible Mount
Garmin GT	PELAGIC
Lowrance 3-in-1	Predator Heavy Duty Mount
Humminbird	Echo H-Duty Mount
Airmar 1KW	ABYSS Mount
Lowrance Active Image HD	A.I.M Transducer Mount

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📖 For the full detailed guide, visit:
https://tigintegrity.com.au/blogs/news/transducer-setup-secrets-complete-guide

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TIG Integrity — Built for the conditions a factory mount was never intended to handle.