designing a fast rowboat

Middle Path Boats Skua

Wow, I just came across the cool web page for Middle Path boats (which I can't believe hasn't popped up in the past 73 pages). Granted, they don't sell plans or kits, just boats, but I really enjoyed their webpage and philosophy, and I would think their faq and outlook would be of interest to all the students of hull design on this thread. Can't make up my mind about the looks of that high, ***-in-the-air wineglass transom. They also are a bit high hat regarding keels:

http://www.by-the-sea.com/middlepathboats/index.htm




This is their 16 footer, which can be rowed even while swamped:

 

Guideboat Double

I have raced against a husband wife team who row a beautiful 18' black guideboat. I finished 10 seconds behind them one year, but I worked a lot harder than they did.

 

easy

did you ever notice how every one seems to be rowing easier than you are and going faster too? RE Skua I rowed one about 5 years ago and didn't like it very much. They are a good boat and have won the Blackburn Challange in the past. It probably just was that the set up was so different from what was used to

 

The way this thread has gone, there have to be some readers curious about a skin-on-frame Adirondack guide boat. I found a page where they built two nice ones together in two weeks.

http://www.capefalconkayak.com/adirondackguideboat.html

 

*Edit* I take back some of my admiration for the originality of the Middle Path Skua boats. Look at this Lake George boat from the 1890's built by Berkshire. I have to say that in the contest between 21st Century computer tech and 19th Century master craftsmen, the craftsmen are kicking some *** on this thread:

http://berkshirewoodenboat.net/prod01.htm

 

One problem: with a waterline length of less than 16' and a waterline beam approaching 40", the Lake George boat doesn't really deserve to be called "fast".

ETA: I should add that there's nothing really wrong with the Lake George boat. It's a nice rowboat if a nice rowboat is what you want. It just wouldn't be one of the faster boats in this thread.

 

I linked to these back on page 22 of this thread but it doesn't hurt to repeat things as not many people would read through this entire thread.

 

So you did, good for you. I hate missing that. I have read the whole thread, and followed most of the links, but when I started I didn't know shinola (I was looking to build my own rocat-like cat) and now I feel like I have a phd. I probably need to re-read the whole damm thing to really know everything there is to know. Lately, I've been reading threads from Woodenboat forum, and that australian forum.

 

I'm skeptical about the Skua...it looks like it has more freeboard than I would like in a boat...and without folding outriggers on gunwales of any boat under 40" we are constrained to very short oars and therefore a short stroke/high rating which isn't always the best stroke depending on the conditions and the rower. One of my business partners/collaborators just obtained a used Skua, so I will reserve final judgement for when I get to row his boat.

I do think Andre's quest for a perfect fixed seat rowboat is admirable. It has been a project for me, too, to find exceptional fixed seat rowboats that can also suit the sliding seat folks.

It is important to stress the importance of the oars in this quest for the perfect rowboat. They have to be light and balanced, with a length that matches rower and boat, and with a certain degree of flex to match the use, and a blade area/shape that also matches intended use. There is no equation for the right combination!

Andrew Steever has been a great teacher for me (his book Oars and Rowing by Mystic Seaport) and his love of the St Lawrence River Skiff has brought me to where I am now, which is very busy bringing back two SLRS's. One is Annie an 18'er and Bobby a 21'er. I'm getting them modeled in the computer, currently. These hulls are really beautiful. And something that pretty usually means FAST! If folks are interested, I'll share some of the computer models.

Cheers

 

Clint,

What software are you using, and yes, please share.

 

Rhino

 

I noticed the effect big-time a few years ago, when I slid my very short kayak several feet up on an ice floe that I thought I could push out of the way: turned out to be a bit bigger than I expected. This was followed by frenzied paddlework as I tried to simultaneously pull myself off the floe and keep upright while leaning forward to keep the water from climbing up the aft deck into the cockpit. Lifting a boat out of the water does nasty things to the stability. I didn't know the same thing can happen over a wave trough.

 

Yup. It's a well known problem. Most of your stability comes from the more-or-less midships sections. If those are out of the water due to a trough, and only the ends of the boat are immersed, the effect is similar to when you stand in the end of a small boat. It gets tippier.

Stability also decreases on wave crests, which you can really notice when taking them on the beam. Basically, waves are a bloody nuisance and I want to know who's responsible.

 

I think it's rather ugly the way they have done the stern. I notice that on their site they compare themselves to Rushton. Given the standard of detailing and proportion turned out by Rushton, I can't help thinking that they are over-rating themselves. In comparison, their work is rather clumsy looking.

My bet is that Annie wont beat a guideboat if the people rowing each are equal. There's no mystique about guideboats when it comes to why they win races. They have mystique regarding the whole "guideboat thing", but that's nothing to do with drag. If you really compare the lines of a guideboat to the boats they regularly beat it's dead basic, staring you in the face obvious why the guideboats are faster. I'm not saying this to be rude, just pointing out that there's no need for anyone to be bamboozled by their speed. Anyone posting in this thread can understand it if they make the effort to do the comparison.

Put simply: the guideboat has similar length, a high prismatic, and very light weight. This gives a slight reduction in wave drag, which is useful. The big gain though is due to the comparatively radical midship section of the guideboat. This gives a much narrower waterline beam than the boats it is up against, and this gives a substantial reduction in wetted surface. Since wetted surface is the majority of the total drag (somewhere around 70% at a rough guesstimate) this means the total drag of the guideboat is a lot lower. No suprise that it's faster, then.

The overall beam is irrelevant. It's what's in the water that counts. An SLRS may have a similar overall beam but it has a different midship section, with a much lower and fuller bilge. This means more wetted surface. Do the math.

Short version: if you want something that will beat a guideboat it will have to be more extreme, not less extreme. Thems the breaks.

Oh and I still reckon the Sausalito wherry is one of the most gorgeous things mentioned in this thread so far. Somebody must have plans for it as it's obviously a fairly new boat, since the construction appears to be glued lap clinker ply.



Obviously, this is not a boat for rough water.

 

Rushton turned out various grades of boats at various prices. For example in 1903 the 20' version of the Idaho, essentially a Saint Lawrence River Skiff, was offered in Grade AA for $190, Grade A for $145, Grade B for $105 and Grade C for $85. Rushton was also a volume manufactuer who had a knack for turning out a good boat for the price. But I'm not sure they were as exceptional as they are considered today.