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.
A heavy planing-hull aft-cabin cruiser that Loops well only when diesel-powered. Air draft and draft both want measuring rather than assuming; fuel economy and engine access are the watch-items.
The Sea Ray 420 Aft Cabin is a roomy, ~20,000 lb (loaded ~30,000 lb) planing-hull motoryacht that was offered with both gas (7.4L MerCruiser) and Caterpillar 3116/3126 diesel power over its run. For the Great Loop the diesel boats are strongly preferred; gas versions are widely considered underpowered and thirsty. Air draft (~15'6" per a brochure) and draft (~3'1") are favorable, but the planing hull burns heavily at any speed and true economy comes only at slow displacement speeds. Known model-specific issues include aft-cabin kick-out panel leaks, generator-dependent 110v/220v systems, and very difficult in-hull engine removal.
Nothing on this page contacts
YouTube until you ask it to.
How to read the tags on this page.CLAIMstated by one source, not yet confirmedQUESTIONopen, and settled by looking at the boat itselfCONTEXTbackground on how this model is built or usedSources are linked where published.
Cat diesel burn has a sweet spot around 2200 rpmPer the forum Cat specialist (per engine): 350hp 3116 ~11.3 gph @2400 rpm; 385hp 3126 ~11.7 gph @2400; 420hp 3126 ~13.0 gph @2400. All show a sweet spot near 2200 rpm at ~9.0/9.1/10.0 gph respectively. Double these for the boat.src:
Club Sea Ray (Cat specialist 'FrankW')
CONTEXT
Real-world diesel burn: heavy at cruise, much better dead-slowA 420 AC owner with Cat 3116s (350 gal) reports ~22 gph at 17 kt cruise for ~250 nm range; slowing to ~8 kt drops burn to ~3.5 gph for ~750 nm. A comparable 410/3126 sips a little over 2 gph at ~7.5 kt approaching 3 mpg.src:
The Hull Truth; Club Sea Ray
CONTEXT
Planing hull: slowing down helps less than expected mid-rangeAs a planing hull, running at 10-12 kt burns nearly as much as being on plane. Best economy is either well up on plane or well below hull speed (~7-8 kt), not in between. A tester noted it 'burned a lot of fuel at any speed' compared to true trawler hulls.src:
Trawler Forum
Air draft & Draft
CLAIM
Low air draft and shallow draft are favorable for the LoopBrochure/listing figures suggest a modest air draft (a listing cited ~15'6") and a shallow draft (~3'1"). The boat carries a radar arch/antennas that add height. Confirm what can be lowered. The buyer must measure the actual air draft (with arch and antennas) on the specific hull rather than trusting the brochure.src:
A classified listing for a 2000 420 AC
Your move: Measure the real air draft with the arch and all antennas in place and identify what can be lowered.
Systems
CLAIM
Refrigeration and A/C are shore-power/generator dependentFridge and freezer are 110v and A/C units are 220v, so at anchor the generator must run to keep refrigeration going, and dockside you need a 50A 220V hookup. One owner budgeted the generator at ~3/4 gph running 2-3 hours a day. A meaningful Loop consideration for anchoring and shore-power planning.src:
Club Sea Ray (420AC owner threads)
CLAIM
Aft-cabin kick-out hatch/panel leaks are a recurring complaintThe aft cabin kick-out hatch/panel is a known, model-specific leak point. Multiple owners report persistent leaking even after gasket replacement, and evidence of prior owner caulking attempts.src:
Club Sea Ray (420AC thread)
CLAIM
Underwater exhaust pipes are vulnerableAn owner knocked off an underwater exhaust pipe in open water and only discovered it when aft bilge pumps kept cycling. Worth inspecting these fittings.src:
Club Sea Ray (2001 420AC owner)
Reading the boat
QUESTION
Does the bilge take on water only after running, suggesting deck-seam or shaft-seal leaks?Owners report hard-to-trace bilge water intrusion. If the bilge fills only after running, water may be entering through a failed deck-seam seal or running gear. Check whether bilge intrusion correlates with use.src:
Club Sea Ray
Your move: Ask the owner/broker whether the bilge takes on water underway vs. at rest, and inspect deck seams and seals.
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.
Follow the Sea Ray 420 Aft Cabin. One short email when something
new lands on this page. Only when there's news, and one click stops it.
Looking at a specific 420 Aft Cabin?
This page is the model's story. The product reads an actual listing against it:
your requirements, the hard gates, the record cross-checks, and questions ready
to send.
See a full
sample dossier first if you like.
I'm building an owner's file for this model, with checklists written
for her systems. Want to know when it opens?
What's in it
Spotted something wrong or have first-hand knowledge of this model?
Email support@caniloop.net. Corrections are
how a profile earns its Facts, and we credit them however you choose.
This profile reflects sources opened and verified by a person. It's buyer homework, and
it makes no judgment on any particular hull.