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Model profile · for Great Loop buyers
Ranger Tug R-31
What the published record establishes about this model, what owners report,
and the questions worth asking while a boat is still a listing. This page is about the
MODEL — a specific hull always gets its own homework.
An efficient, Loop-friendly single-diesel trailerable tug whose main watch item is Volvo D4 overheating at higher RPM in warm water.
The Ranger Tug R-31 is a single-diesel, semi-displacement trailerable cruiser popular on the Great Loop for its efficiency at displacement speed and its folding flybridge/mast that gives it a low folded air draft. It came in two body styles — the CB (Command Bridge, with flybridge) and the S (Sedan) — powered by a single Volvo Penta D4 (roughly 300 hp on earlier boats, 320 hp later). The dominant owner-reported concern is D4 overheating at higher RPM in warm water, which matters on the Loop's hot southern legs. Note that the primary owner forum (Tugnuts) is builder-owned and moderated, so weigh its positivity accordingly.
How to read this: 🟢 Fact = confirmed against a document, spec sheet,
or owner. Everything else — Claim, Pattern, Question, Context — is not yet
verified: things to check, not settled truth. Sources are linked where published.
Access & Service
CLAIM
Engine access is tight and a common owner complaint
Engine access is consistently described as restricted — owners mention mechanics groaning at the cramped space and note the smaller diesels are hard to reach for repairs. Opinions differ (one owner said there is enough room working from the top on the 31), but expect labor-hours to run higher for anything involving the outboard or aft sides of the engine.
src:
Trawler Forum; Tugnuts owner threads
Air draft & clearance
CLAIM
Folding flybridge and mast give a low folded air draft — a key Loop strength
The R-31's flybridge (CB) and mast fold down, giving a low folded air draft that is a major selling point for the Loop. Clearances differ by variant: the CB (Command Bridge/flybridge) folds lower for trailering than erected, and the S (Sedan) is a lower-profile boat. Published figures typically exclude add-on antennas.
src:
rangertugs.com; PropTalk; Soundings
Your move: Measure the actual air draft of your specific boat with everything lowered, and identify exactly what folds or unships (mast, antennas, radar) versus what is fixed.
CONTEXT
Lowering the mast is a manual step owners have forgotten — with damage
Because clearance depends on actively folding the mast and bridge, the low air draft is only real if the crew remembers to lower it. One owner who forgot reported an ugly crunching noise and a loud bang. Build a pre-bridge checklist.
src:
Tugnuts owner threads
QUESTION
Is this a CB (flybridge) or S (Sedan), and what is the erected vs. folded air draft?
The two body styles have materially different profiles and clearances, and the erected height matters for marina roofs and lifts even though the folded height governs bridges. Knowing which variant you are looking at changes the whole air-draft picture.
src:
rangertugs.com
Your move: Confirm the exact variant (CB vs S) from the HIN/build sheet and measure both the folded and erected air draft on the actual boat, including any added antennas.
Handling & Range
CLAIM
Semi-displacement hull — efficient slow, steep fuel climb toward semi-plane
The R-31 is semi-displacement, not a true planing hull. It is very efficient at displacement speed — boat tests report roughly 1.5 gph and ~4.7 nmpg at 7 knots (D4-300), and ~4.2 nmpg at 6.6 knots on the D4-320. Fuel burn climbs steeply between hull speed (~8 knots) and semi-planing (~13 knots), then flattens; a comfortable ~15-knot cruise yields roughly 2 nmpg. Loop cruising is normally done at the efficient low end.
src:
Soundings; Power & Motoryacht; PropTalk; Tugnuts owner reports
CLAIM
Fuel capacity around 180 US gallons
Fuel capacity is commonly cited around 180 US gallons. At displacement/Loop-cruise speeds this gives comfortable range, but usable range shrinks sharply if run at semi-planing speeds. Plan fuel stops around the speed you actually intend to cruise.
src:
Manufacturer specs
Your move: Confirm the tank capacity on the build sheet and calculate usable range at your intended cruise speed, keeping a reserve.
Reading the boat
CONTEXT
The primary owner forum is builder-owned and moderated
Most substantive owner discussion is on Tugnuts.com, which is owned and moderated by the builder (Fluid Motion). Owners on Trawler Forum and The Hull Truth report that critical threads — especially about quality issues — have been deleted there, so the forum skews positive. Weigh Tugnuts feedback accordingly and cross-check on independent forums.
src:
Trawler Forum; The Hull Truth
QUESTION
What is this boat's build-quality and warranty history, given third-party quality complaints?
Independent forums point to a minority of Ranger/Cutwater owners reporting significant quality problems (including a disgruntled owner who built a complaint site). This is not universal, but it makes a documented service and warranty history worth having on any specific hull.
src:
The Hull Truth
Your move: Ask the broker and, if possible, prior owner for the full service and warranty-claim history, and have the surveyor look closely at deck/hardware fit and finish.
Engines
The engines research — factory options, tested performance,
and the engine-specific questions our members' dossiers carry — is part of the
full profile inside the product. It travels with every dossier and survey brief
built on this model.