Everyone calls the 30-foot speed boat the “sweet spot.” After a couple decades of owning and crewing everything from 24’ hot rods to 40’ offshore rigs, I’m not convinced. In real water, it looks more like the worst compromise: too big to trailer everywhere, too small to keep you fresh when a forecast goes sideways, and shockingly thirsty once you try to hold a fast cruise in chop. Before we keep pretending the marketing sheets translate to the ocean, can we get real about this size class?
Here are the specific claims I’m challenging and what I’d like data or hard-earned experience on:
Power choices and drag: Twin big-blocks/supercharged outboards vs triples. On a 30’ hull, does the third outboard ever pay for itself in midrange efficiency and head-sea control, or is it just top-end fluff and extra drag hanging off the bracket? Anyone log fuel flow at 25-45 knots in 1-3 ft chop with twins vs triples on the same or similar hulls?
Stepped vs non-stepped hull safety margins in quartering seas: The brochure speed gains are clear. The part nobody publishes is how often you get aeration/ventilation weirdness when trimmed for economy and a quartering back sea builds. Has anyone instrumented trim angle, slip, and RPM excursions to show what actually happens at 35-50 knots in a confused sea state?
CG shift and tank placement: A lot of 30s put fuel midships but still move the longitudinal CG a surprising amount as tanks empty. That correlates with porpoising and “tab crutches” at mid-cruise. Have you measured LCG changes across a full fuel burn and found a repeatable fix beyond “more tab”? Battery relocation, forward water ballast, or interceptors solving it better than tabs?
Real human comfort per gallon: I care less about WOT and more about how far I can run before the crew starts bracing knees. Has anyone built a comfort-normalized fuel metric, like gallons per nautical mile at a set RMS vertical acceleration (say 0.15-0.20 g on a phone IMU)? I suspect many 27-28’ hulls beat 30s here, and 33-34’ steps beat them both, making 30’ the least efficient “comfort per gallon.”
Structure and transom life with modern power: We’ve normalised hanging 900-1200 hp off a 30’ transom. Are we quietly chewing through brackets, knees, and stringers with high-frequency slamming loads? Any owners borescoped or strain-gauged after 300-500 offshore hours? Insurance rebuild anecdotes welcome.
Real LOA and moorage penalties: A 30 with a bracket and triples is effectively 32-33’ for the slip bill. Anyone actually save money by picking a lighter twin setup and keeping the bracket shorter without sacrificing practical range/speed?
If you’ve got data logs, even better. A simple community test would settle a lot:
- Pick a 5-7 nm upwind then downwind loop in 1-3 ft chop.
- Log GPS speed over ground, fuel flow, RPM, trim, tab/interceptor setting, and vertical acceleration from a phone IMU (mount solid to the deck).
- Run steady-state passes at 22, 28, 34, 40 knots where safe.
- Post the CSV and note hull, power, prop, load (crew, fuel %, water), and sea state.
My hypothesis:
- 27-28’ deep-V with efficient twins offers better comfort per gallon below 40 knots.
- 33-34’ stepped hulls with twins or big twins offer better comfort and similar total operating cost than a 30 with triples at the same real-world cruise.
- The 30-foot “sweet spot” mostly shows up in flat-water demo rides and spec sheets, not in an honest day offshore.
Convince me I’m wrong with numbers, not brochures. Who’s got logs, or is willing to run the test next blowy Saturday?