What is the difference between BAFFLES and BULKHEADS in a liquid tanker, and how does each affect surge?

BAFFLES and BULKHEADS serve different surge-control functions and produce different handling characteristics: BAFFLES: Perforated or slotted internal partitions that span the cross-section of the tank; liquid can flow through the openings, but the restricted flow DAMPENS front-to-back (longitudinal) surge; the liquid cannot surge as freely during braking and acceleration; baffles do NOT prevent side-to-side (lateral) surge — they have limited effect on handling in turns; a baffled tanker is better for straight-line braking but still susceptible to rollover in turns due to lateral surge; BULKHEADS: Solid, impermeable dividers that create completely separate compartments; liquid CANNOT flow between compartments; surge within each compartment is limited by its size — a smaller volume surges less; bulkhead tanks can carry different products in different compartments; UNBAFFLED TANKS: Some tanks (particularly smooth-bore tanks for certain food-grade products) have NO internal divisions — these have the most severe surge characteristics and require the most conservative driving; PRACTICAL IMPLICATION: Even a baffled tanker requires significantly more braking distance than a solid-load vehicle of the same weight; the surge forward during hard braking can actually accelerate the vehicle briefly before braking takes effect — this is the 'wave effect' that makes tanker driving different from other CMV driving.