True North Mackinaw Tender

Over the winter of 2025/26 we worked to research and design our own boat for our newly formed "Pirates Club" Inspired by the nearly extinct working Mackinaw boats once common in Bayfield, Wisconsin and the Apostle Islands, the True North MackinawTender brings 19th-century Great Lakes practicality back to life through a thoughtful 21st-century design. It is a deliberate blend of traditional form and modern materials, building methods, and boating sensibilities. 

Stable, forgiving, and quietly capable, the Mackinaw Tender is descended from the true workhorses of the lakes—boats that bridged the era between birchbark canoes and outboard motors. That heritage translates naturally to today’s needs, offering a safe, confidence-building platform for both children and adults to experience time on the water together. 

Equally at home rowing or sailing, the Mackinaw Tender invites unhurried exploration: rowing with friends, teaching kids the feel of wind and water, or discovering traditional sailing without intimidation. Its shallow draft and natural stability make first sails approachable and shared rowing easy, while its capacity allows for camping gear and small expeditions—capable of crossing channels to nearby islands and staying awhile once you arrive. 

Light enough to pull up on a beach, trailer behind a car, or launch somewhere new, the Mackinaw Tender is designed for curiosity and freedom. A simple, honest balanced lug rig keeps the focus on the experience rather than complexity, making it ideal for multi-generational ages to experience time on the water together or alone. 

This small rowing and sailing double-ender is not about speed or spectacle. It’s about the journey—from building the boat with your hands, to reaching distant shores at your natures pace. The True North Mackinaw Tender is an invitation to slow down, learn, and reconnect—with the water, with tradition, and with each other. 

Concept & Character of the True North Mackinaw Tender 

This boat is a small Mackinaw-inspired working craft, scaled and refined for hands-on learning, rowing, and simple sailing rather than commercial freight. It takes its cues directly from the Bayfield, Wisconsin Mackinaw boats of the late 1800s—boats that were expected to: 

● Carry people and gear safely between Bayfield and the Apostle Islands ● Rowed efficiently in calm or rough water, take choppy cold waters from the bow or stern ● Sail simply, without complex rigging 

● Remain stable with mixed loads and inexperienced crews 

The design preserves these traits while adapting them for our modern beginners, families, and youth programs of today. 

Key Bayfield and Apostle Islands heritage elements reflected in the hull: 

● Full, buoyant mid-sections (working-boat stability) 

● Moderate beam for form stability without excessive drag 

● Double-ended Mackinaw form for predictable handling 

● Near vertical stem and raked sternpost 

● Shallow draft for beaching and near-shore use (Kick-up swing keel and rudder) 

● Strong initial stability with gentle secondary stability 

This is not a racing dinghy and not a tender—it’s a small working boat meant to be learned in, and trusted. A boat that can take a load. Great for traditional travel between islands, Capable of taking a load for camping expeditions. Stable platform for kid groups to learn to sail and row. 

Why It’s Ideal for Beginners → Intermediates Stability & Confidence 

The hydrostatic data shows exceptionally high initial stability for a boat of this size: 

● Initial GMt ≈ 3 ft 9 in (lightship) 

● Max righting arm ≈ 1 ft at ~44° heel 

Large reserve stability well past typical sailing angles 

What this means in practice: 

● Beginners feel immediate confidence 

● Kids can move around without upsetting the boat 

● Gusts and sudden weight shifts are forgiving 

● The boat resists sudden knockdowns 

This is exactly what you want for first-time sailors and rowers. 

Rowing & Sailing Learning Platform 

Because the hull is: 

● Narrow enough to row efficiently 

● Wide enough to be stable 

● Long enough to track straight for longer passages between islands. 

…it works exceptionally well as: 

● A multi-oar rowing trainer 

● A balanced lug sailing classroom 

● A transition boat from rowing → sailing 

You can row first, then introduce sail later—mirroring how historic Mackinaw crews learned. Mixed Crews (Kids + Adults) 

The displacement curve shows the hull scales smoothly with load:

From the hydrostatics (page 2): 

● Stable trim maintained from ~150 lb to 900+ lb displacement ● Beam at waterline increases naturally with load 

● No sudden loss of stability with added weight 

This makes the boat suitable for: 

● Multiple kids rowing together 

● 1–2 adults with children 

● Adult instructor + youth crew 

● Mixed rowing/sailing sessions 

It is not weight-sensitive, which is critical for group and expedition use. 

Specifications 

Values below are taken directly from the Hydrostatic Calculations and CAD geometry. Where ranges exist, Below are realistic operating values. 

Hydrostatic Calculation.pdf

Download PDF • 269KB

Principal Dimensions 

● Length Overall (LOA): ~14ft 1in 

● Waterline Length (typical load): ~13 ft 1 in 

● Beam (max): ~4ft 6in 

● Rowing Draft (lightship ~200 lb): ~3.2 in 

● Rowing Draft (moderate load ~450 lb): ~4.8 in 

● Heavier load draft (~750 lb): ~6.5 in 

● Draft with Centerboard Swing Down - 18” - 24” 

This is a very shallow-draft boat, ideal for near-shore work, beaching, and teaching environments. 

Displacement & Payload 

● Hull Weight (lightship): ~200 lb 

● Comfortable Working Load: 450–750 lb 

● Maximum Practical Payload: ~900–1,050 lb 

(At 900 lb displacement, stability and trim remain well-behaved per hydrostatics.) 

Stability (Key Teaching Feature) 

● Initial GMt: ~3 ft 9 in 

● Max GZ: ~1 ft at ~43.6° 

● Large positive righting arm through typical sailing angles 

This is exceptional stability for a 14-ft boat and strongly supports beginner use. Sail 

Compatibility (Design Intent) 

● Rig Type: Balanced lug (mast stepped through forward bench) 

● Target Sail Area: Main sail “full power” ~85 sq ft Jib: ~15 sq ft 

Reef plan: 

● Reef #1: drops you to ~65–70 sq ft (your “training/default” mode) 

● Reef #2: drops you to ~45–55 sq ft (heavy air / kids / gusty Superior days)

● Mast Placement: Forward, with mild aft rake via partner geometry 

After our first boat is completed and proven we will have the CAD files available to download and share!

The True North Mackinaw Tender is inspired by our local history!

Huge thanks to the Bayfield Heritage Association for sharing these images and for all they do to preserve our local history. Most of these pictures are taken from the beach right next to the True North Dock where we plan to keep the boat.