Commuting by boat?

I've been thinking about commuting to work by boat.

It takes about 43 minutes each way for me to drive the 25 km to work and back (average speed is just under 35 k per hour).

I live on the water and work in a marina. The distance on the water is about 7nm.

On the face of it, all I need to do is have a boat that can average about 10 knots to get equal commute time. The last mile is through the Second Narrows and the tidal current can run 6+ knots at times.

If I could average 15 knots, my commute goes from 43 minutes to under 30 minutes.

I burn about a gallon of fuel each way in the car.

Would it be possible to average 15 knots burning 2 gallons per hour? (to make the fuel costs equal)

What kind of boat would be able to have that sort of performance?

 

I wish I had your problems,longliner

 

Come on up! We have lots of space and cold beer ...

 

Get an efficient planning hull (speed boat) with diesel(s) like a yanmar 440. You can cruise very efficiently at 4+ mpg at much faster speeds.

 

I need a boat that will do 7nm /gal at 15 knots.

If the formula Gallons/hour = HP/15 is correct (the most accurate number I have) that means a 30 HP engine.

What would a 30HP 15 knot + cruise speed hull look like?

What would the boat have to weigh?

Does anyone build a boat that would fit?

Campion makes a 622 Explorer that looks like an all weather boat, but it weighs 4000 pounds and the smallest engine is a 1.7 liter 120HP with Alpha outdrive ...



I don't think this will have anywhere near a 2 gallon/hour fuel burn.

I think something like this scaled to a 25-30 HP 4-Stroke OB would be a great boat.

Another option would be something like a Bolger Sneakeasy

 

Yes you definately need a long and lean hull, like a commuter boat. Look for something along the lines of 6-10:1 length to beam ratio So if you built a boat with a 5' beam at a 6:1 ratio for 30 ft. 2* sq rt of the wl length...say 28 ft is about 10.6 kts or around 12 miles/hr...38 minutes commute. boost that to 2.5 factor (more HP) and you are looking at 13.25 kts or around 15.5 mph and around 30 min. At 33 ft WL length and 2.5 factor you have 14.35 kts or 17 mph and under 30 min commute. These numbers are just a rough guess but are ballpark good. Your fuel mileage won't be as good as a car's tho, not for the amount of time traveled at speed. There is simply too much resistance to overcome VS a car on well greased bearings with only a few square inches of contact with the road. Wind resistance is negligable in relation to water and wave resistance... I don't know if you could build a boat light enough to plane or semi-plane with 30 hp at the length needed to give the needed ratios. Perhaps a simple shell of a boat, built of ply via stitch and glue method, with minimal framing and the lightest ply that would serve. Were you to compartmentalize it with sealed bulkheads you might obtain the needed stiffness, I don't know. I do know it would be one heck of a boat to save 30 minutes travel time...you are better off getting a motorcycle and slipping thru traffic, at least for most of the year. I spent Jan thru Mar on an Island off of Vancover Island between VI and mainland BC. It was cold but it never snowed so I expect you could ride most if not all of the year.


Steve

 

I used to ride my motorcycle to work. Except for a few days when there is snow on the ground, I rode in year-'round. In 2002 I got hit head-on by a car that crossed over the double yellow into my lane. After I healed up enough to ride again I found that I am gun-shy in traffic, so I gave up on riding to work.

I'm not looking to get car-like fuel economy, I'm just curious what is possible. I know that 5-6 nm/gal is possible at 5-6 knots, but that's not fast enough to be an alternative to commuting by road.

The Bolger Sneakeasy is 27' x 4' and with 25HP will do over 30MPH ... it might just fill the bill. I have no idea how a flat bottom power sharpie would handle in less than calm water.

This 16' Vee bottom from Glen-L might be able to do the job also ...

16' Cabin Skiff

 

Think catamaran,two hulls slicin thru the water.

 

Check out Tom Lathrop's (known as Tom28571 around here) Blue Jacket 24. She should achieve the kind of economy you're after

http://www.bluejacketboats.com/index.htm

(You can send me my cut later Tom! )

 

Build a boat with a cabin that you can sleep in and don't go home every night.

 

The place to start the math is a 14' aluminum boat with windshield and canopy, and the smallest 4 cycle outboard that will get it up on plane.

 

Any speed limit?



These will go over 50 mph with a 25 hp outboard burning about 3 gallons per hour.

 

Of course you'll be soaked to the skin by the time you get to work - if you make it that is...
But you will have a BIG smile on your face!

 

I'd be really leaning towards a wavepiercing cat shape here. Very long, slim hulls with minimal wave drag, fairly light overall. If it were me, I'd be giving equal consideration to a sharpie monohull- not necessarily a planing form, though. Efficiency doesn't come from brute force, but seems to go hand-in-hand with grace and finesse. So a slim, elegant hull, low wave drag and not much slamming in seas.....

 

Bolger's Sneakeasy at 26-1/2 ft x 4 ft should do 30+ mph on 25HP ... If HP/15 is a decent guesstimate for fuel, 30 mph on 1.66gph = 18 mpg.

I like the look ... the big question is how a 26ft long 4ft wide flat bottomed sharpie would handle anything but smooth water. Bolger has also drawn a "Step Sharpie" version where a cutwater continues aft as a box keel.



A soft top or small hard top would make it into an all weather boat ... if ... the step sharpie hull form handles well ...