Marine Antifoul Removal with Dry Ice — A Yacht Owner's Guide

A full antifoul strip-back is a once-a-decade job for most yacht owners. The choice of method matters because the wrong choice damages the hull beneath the antifoul — and that damage is expensive to fix. Here’s a clear-eyed look at how dry ice antifoul stripping compares to the alternatives.

Why a full strip-back?

Antifoul builds up over the years. Each new coat goes over the last; eventually the layered build-up cracks, becomes uneven, and the protective system fails. Symptoms:

• Visible cracking and flaking when the boat is hauled out
• Antifoul performance dropping despite recent recoats
• Texture rough enough to grow biofouling on top of the antifoul
• Total thickness exceeding 1-2mm

When this happens, recoating won’t fix it. You need a strip-back to bare epoxy barrier coat (or in some cases the original gelcoat), then re-prime and re-coat from scratch.

The methods compared

Sandblasting

Fast, cheap, well-understood. The trouble: sandblasting is abrasive on the gelcoat under the antifoul. On older boats with thinning gelcoat, this can crease into structural risk. On newer boats with thicker gelcoat, the gelcoat texture is left rougher than it should be — affecting future antifoul adhesion.

Verdict: viable for steel and aluminium hulls, problematic for GRP / gelcoat hulls.

Chemical paint stripping

Dissolves the antifoul layer chemically. Effective, but creates two problems: chemical waste handling (hazardous), and run-off into marina water (often prohibited by marina compliance).

Verdict: increasingly restricted by marina rules; environmental disposal cost is significant.

Hand sanding / mechanical scraping

Slow, labour-intensive, and easy to gouge gelcoat. Only really viable for spot work, not full strips.

Verdict: only for small areas or touch-up work.

Dry ice blasting

Non-abrasive on gelcoat. Captures all flake on ground sheets — zero run-off into marina water. Pressure-tuned per surface. Slower than sandblasting per square metre but fast enough that 38ft cruisers are 2-4 day jobs.

Verdict: the right tool for GRP / gelcoat hulls, where preserving the substrate matters.

What the work involves

A typical 38-42ft cruiser antifoul strip-back:

Day 1. Setup, containment, and one side waterline-down. Containment is full ground-sheeting under the hull to capture flake. Pressure tuned around 100-110 PSI.

Day 2. Other side, plus the underside.

Day 3. Bow, stern, transom, keel detail work. Cleanup and disposal.

For larger vessels (50ft+), add a day or two. For smaller vessels (under 30ft), 1.5-2 days is typical.

What gets revealed

Once the antifoul is off, you can see the hull condition for the first time in years. Common findings:

• Osmotic blistering. Bubbles or pitting under the gelcoat caused by water absorption. Treatment: epoxy peel and re-coat. Common on older GRP hulls.
• Stress cracks. Hairline cracks in gelcoat from impact or flex. Treatment: gelcoat repair before re-coat.
• Through-hull issues. Old fittings, deteriorated seacocks, loose skin fittings. Treatment: replace before re-coat.
• Sound hull. No issues, ready for fresh barrier coat and antifoul.

The shipwright works alongside the cleaning crew to flag any of the above. Repairs happen between strip-back and re-coat.

Cost

Antifoul stripping is in the Industrial tier ($1,800-$8,500+ base, with condition multipliers).

Typical pricing:

• 30-35ft cruiser: $3,500-$5,000
• 35-42ft cruiser: $4,500-$7,500
• 42-50ft cruiser: $6,000-$10,000
• 50ft+: $8,000+ depending on size and complexity

Add to this:

• Hard-stand / slipway fees (charged by your marina, not us)
• Disposal of antifoul flake
• Shipwright work for any hull repairs revealed

We’re typically not the most expensive option (chemical stripping and aggressive sandblast cleanup can cost more) but we’re rarely the cheapest. The value is in the gelcoat preservation — saved gelcoat means more years of effective re-coats before structural intervention is needed.

Marina compliance

Most Australian marinas now require some form of containment for hull-strip work. Dry ice cleaning satisfies this without additional infrastructure:

• Zero water-borne run-off
• Solid antifoul flake captured on ground sheets
• Disposal documented and certified

We provide a disposal certificate as part of the handover pack — useful for marina compliance records.

How to plan a strip-back

1. Hard-stand booking. Marina or slipway booking secured, dates locked in.
2. Shipwright engagement. Shipwright walks the hull pre-clean, identifies likely repair zones.
3. Cleaning quote. Send us photos and dimensions; we come back with a fixed quote.
4. Strip-back. 2-4 days typical for cruiser-size boats.
5. Repairs (if needed). Shipwright addresses anything revealed.
6. Re-coat. Fresh barrier coat + antifoul. Often a separate provider.

The whole sequence from haul-out to re-launch is typically 1-3 weeks, depending on what the strip-back reveals.

How to engage

Send us a brief with vessel details (make, model, length, hull material, antifoul history). Photos help — particularly close-ups of any visible cracking or texture issues. We come back with a fixed quote within 24 hours.

For multi-vessel work (charter fleets, marina partnerships), we can arrange contract pricing. Email office@dryiceblasters.com.au.