Monday, June 18, 2012

Spira International 27 Foot Boat Plans Build Costs

This will be my first keel up boat build.Well,unless you count the single person knock together boats I have built.I have rebuilt and restored a number of boats by myself and with friends.I even held a job doing interiors and upholstery in boats.

The one main factor is the cost of building the hull and cabin.I will layout the cost to build the 27 foot trailerable Spira International boats.I am using the bill of materials(BOM) off of the study plans that are available on the Spira International website.It's good to be able to get an idea of what costs are involved before building.Most other designers require you to purchase a study plan to get an idea of what's involved to build their design.You may still be required to buy the full plan set to get the BOM.This is a bad business practice in my mind.With the BOMs in hand,I started getting the numbers together and adding up cost.I will layout the cost break down and then give some ideas on how to cut some costs.I will start laying out things and end with the boat I have chosen as the design I plan to build.

The Elements of Boat Strength

Suppliers for pricing are as follow.
Lowe's Wood supplies.
Home Depot Wood supplies.
Raka Epoxy and fiberglass.
Fastenal Screws and bolts.
McMaster Carr Screws and bolts.
DuckworksBBS Duckworks carries some of the odd size screws called for in the plans.

Avoid treated woods as much as possible.Treated wood usually contains traces of copper which corrodes fasteners and any other metals that come in contact with it.Even painted it can still leech copper.Also,copper is bad for the marine environment and is illegal to use in bottom coatings in some areas.

I prefer A/B fir plywood but will accept A/C fir,if it's good quality.Avoid plywood with voids and footballs if possible.

I only use stainless steel fasteners for the extra corrosion resistance.Most of them will be sealed in with epoxy.I only use Raka epoxy kits with non blush hardener.

50 inch width is considered standard width for fiberglass boat cloth.Try to purchase all of your fiberglass cloth at one time.It saves a lot of money.

Bahaman Hull only No BOM for cabin.
$105=240 ft. 2x4
$40= 38 ft. 2x8
$60=2x stock for transom splash well
$78=180 ft. 1x4
$75=170 ft 1x4 decking-You can use decking or epoxy coated and painted 1x4 choice is yours.
$50=1x stock for rail cap-A good hardwood works well but is costs more.
$297=9 sheets 1/2 in. plywood
$195=5 sheets 3/4 in. plywood
$219=500 #10x3 in. screws
$196=2000 #8x2 in. screws
$338=5 gallons epoxy
$259=50 yards 6oz fiberglass cloth

You can look at the cost of other models to gain and idea of the cost to build a cabin.I estimate between $300 and $500 depending on length of the cabin.

Hull Only
$264=8 sheets 1/2 in. plywood
$142=10 sheets 3/8 in. plywood
$103=240 ft. 1x4
$79=180 ft. 2x4
$341=1000 #10x2 1/2 in. screws
$30=250 #8x2 in. screws
$76=5/16x4 in. machine screws
$26=5/16 in. nuts
$9=5/16 in. washers
$60=12 ft. 5/16 in. threaded rod-washers and nuts included above price
$5=four 1/4 in.x 4 in. lag screws
$338=5 gallon epoxy
$25=3 in. glass tape 50 yards
$311=60 yards 6oz fiberglass cloth

$36=80 ft. 1x4
$99 =3 sheets 1/2 plywood
$25=250 #8x1 1/2 in. screws
$30=deck finish

$29=62 ft. 1x4
$58=2 sheets 5/8 in. plywood
$165=5 sheets 1/2 in. plywood
$25=250 #8x1 1/2 in. screws
$55=2 quarts epoxy
$46=8 yards 6oz fiberglass cloth
$378 total

$2377 total hull,deck,and cabin

Cane River
Hull only-The cost for Chubasco's cabin would be close.
$284=20 sheets 3/8 in. plywood
$462=14 sheets 1/2 in. plywood
$131=300 ft. 2x4
$47=240 ft. 1x3
$50=55 ft. 2x8
$341=1000 #10x2 1/2 in. screws
$188=100 5/16x4 in. screws
$26=100 5/16 in. nuts
$9=100 5/16 in. washers
$245=2500 #8x2 in. screws
$608=10 gallon epoxy
$622=120 yards 6oz fiberglass cloth
$3013 total

San Miguel
Hull only-The cost for Chubasco's cabin would be close.
$142=10 sheets 3/8 in. plywood
$330=10 sheets 1/2 in. plywood
$172=6 sheets 5/8 in. plywood
$105=240 ft. 2x4
$55=280 ft. 1x3
$16=32 ft. 1x4
$171=500 #10x2 1/2 in. screws
$196=2000 #8x2 in. screws
$798=15 gallons epoxy
$518=100 yards 6oz fiberglass cloth
$2503 total

This is the boat I am planning to build.I will stretch it to 30 feet and build the V entry bow per the plans.
This total will be to build Sitka at 27 feet.Add approximately $200 to $300 to build to 30 feet with the V bow.
Hull Only
$105=240 ft. 2x4
$85=125 ft. 2x6
$30=32 ft. 2x8
$50=100 ft. 1x4
$199=14 sheets 3/8 in. plywood
$396=12 sheets 1/2 in. plwood
$113=6 sheets 5/8 in. plywood
$451=60 yards 6oz fiberglass cloth
$498=8 gallons epoxy
$97=300 #10x3 in. screws
$98=1200 #8x1 1/2 in. screws
$176=60 ft. 1x8
$2298 total

$31=64 ft. 1x4
$141=48 ft. 1x8
$462=14 sheets 1/2 in. plywood
$XXX=12 yards 6oz fiberglass cloth-price included in bulk order above
$182=2 gallon epoxy
$25=200 #8x1 1/4 in. screws

$3139 total for hull and cabin

Newfie.Some may notice that I didn't include Newfie.I really like that boat, but it has a very small interior and there was no BOM on the study plans.

Boat Building Manual

There are some ways to cutting material costs.I added a few above.

Lumber.Find a local saw mill and have the lumber cut to full boat length.You could also use trees from your property.Make a deal to get your lumber ordered filled and let the mill have the rest to sell as payment.This can be tricky as some saw mills are mobile while others require you to haul your wood to the mill.This option takes longer and requires a place to store the wood while it finishes drying out.The best option for most people will be finding a local builder's supply.They get huge loads of lumber with a volume discount.If you buy enough,they sometimes will negotiate for  lower price.Also,there wood tends to be better quality than most places like Lowe's and Home Depot.

Fasteners.I recommend finding a local supplier and purchasing everything at once plus 10% to build the hull and/or cabin.Later when you need fasteners and hardware to finish out the boat,you can possibly negotiate for a slight discount on pricing.Hey,every little bit helps.

Epoxy.Some epoxy manufactures set a shelf life for their products some do not.I have had epoxy either, go bad, or it was a bad batch.Which,I am not sure.Epoxy is heavy and can get expensive.Try to buy in bulk to save on cost and shipping.It's best if you can find a dealer or supplier.Be careful tho.Their mark up may be a lot higher than ordering a kit.Shop around.I like Raka because they have an easy mixing system.

PL glues.I have had bad experiences with these, so I stay away from them.My main gripe is the ability for PL and epoxy to stick together.I built a knock together plywood boat and when I sheathed it in fiberglass and epoxy,the area around the PL let go.I won't knock PL glues, but they're not for me when boat building.

My next installment will include more ways to cut cost during fit out and finishing.

Practical Encyclopedia of Boating


  1. Thanks for the information. Please post photos of your build. I'd like to see your progress.

    1. As soon as the doctor clears me to start work,I will start prepping for the build.

  2. I built one of Spira's 15 foot boats. I used double the BOM estimates for screws and epoxy. The boats great and is holding up well 2 years later.

  3. Hardware will vary by builder.Some feel less is more and others feel more is more.Other than a small increase in cost,there shouldn't be a problem with more fasteners.They are mainly there for holding the panels together until the epoxy dries.