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Ranger Tug R-31

The published record on this model and what owners report, with the questions worth asking while a boat is still a listing. This page covers the model. Every boat still needs its own homework.

The published record

Beam10.0 ft
Draft2'6"
Fuel180 gal
Water60 gal
Holding40 gal

Source: Ranger Tugs R-31 CB and S spec sheets (current). If a listing disagrees with these numbers, the listing may still be right. Settle the difference before it costs you.

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), each 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.

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On video

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How to read the tags on this page. CLAIMstated by one source, not yet confirmed QUESTIONopen, and settled by looking at the boat itself CONTEXTbackground on how this model is built or used Sources are linked where published.

Access & Service

CLAIM
Engine access: owners and a magazine review disagree Some owners describe access as restricted, with mechanics grumbling about the cramped space around the smaller diesels. Soundings' review of the R-31 called access to the centerline engine excellent, with adequate space all around, and one owner said there's enough room working from the top on the 31. Look for yourself before you count on easy service. src: Soundings review; Trawler Forum; Tugnuts owner threads
Your move: Open the engine hatch and check you can reach the filters, raw-water impeller and belts.

Air draft & clearance

CLAIM
10'3" folded on the CB, 10'0" mast down on the S Ranger's current sheets give the CB 10'3" with the bridge and mast down and 18'2" with them up. The S is 10'0" with the mast down and 13'10" with it up. Published figures leave out added antennas, and the erected height still matters for marina roofs and lifts. src: Ranger Tugs R-31 CB and S spec sheets (current); 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, resulting in 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 NM/gal at 7 knots (D4-300), and ~4.2 NM/gal 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 NM/gal. Loop cruising is normally done at the efficient low end. src: Soundings; Power & Motoryacht; PropTalk; Tugnuts owner reports
CLAIM
180 gallons of fuel on the builder's current sheet Ranger's current sheets give 180 US gallons of fuel, 60 of water and 40 of holding for both the CB and the S. At displacement speed that gives comfortable range, but range shrinks sharply at semi-planing speeds, so plan fuel stops around the speed you'll actually cruise. src: Ranger Tugs R-31 CB and S spec sheets (current)
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: The Hull Truth; Trawler Forum
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 is part of the full profile inside the product. It covers factory options, tested performance and the engine-specific questions in our members' dossiers, and it travels with every dossier and survey brief built on this model.

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