Hull shape for simple sailing scow

Hospadar, in starting this thread is asking for a Firebug. It is 8ft by 4ft, simple to build, easy to sail, They have been fitted for rowing and outboard motor. Easy to sail, but challenging to sail well. I weigh 90 kg and in the handicap class manage on occasion to beat Vagabonds, et al. The 'Bug planes a little slower than a Heron, but she will be there at the end of the race, snapping at the heels of their survivors.

 

The Press at Toad Hall has some excellent sailing scow designs it would be well worth your time just to look.

 

This is a very late reply.

Most PDRacers use a traveller across the back of the boat. The disadvantages of running the sheet from the rudderhead are
1/ It adds an extra load so you can't feel what the tiller is doing and how much weather or lee helm the boat has. It can even be tiring to fight the tiller through each gust as the sheet tries to push the back end to leeward.

2/ The sail should never be centred upwind, the normal angle for the front sail when sailing upwind is about 10 degrees from the centreline. It is better for the bottom block (pulley) to be at about that 10 degrees unless there is a vang to hold the boom down or a sprit boom, which also limits sail twist.

There are many interesting features in the PDRacers (or my closely related OzRacer), which made them fascinating to work with for some time. Many that work and some that don't work very well. But the class fulfils its mandate of getting people who often haven't sailed onto the water cheaply in something that can sail rather well if the normal standards of good boat setup and detail design are maintained.

It has kind of taught me that if you get the "wings" right (centreboard or leeboard, rudder and the sail) and their relationship then as long as you don't do anything really stupid with the hull , then it will sail well and might just sail very well.

As far as rigging goes (very late I know, but it is here for perpetuity), here are the information pages for setting up rigging for a PDRacer spritsail and hull and a general page for lug rigs.
http://www.flickr.com/photos/boatmik/sets/72157594524425079/
http://www.storerboatplans.com/GIS/GISRigging.html

Best wishes
Michael Storer
Michael Storer

 

BoatMik, I strongly agree with your comments, any connection to the tiller or rudderhead will interfere with the feel of the helm, and this is particularly important in a small responsive boat.

In the Firebug, the sheet runs from the end of the boom to bridle on the transom, back to the boom and then over the occupants head and down to the front of the centreboard box. In placing the final part of the sheet at the front of the box, Spencer made the space in the cockpit useable for an adult, unlike the Sabot and the Optimist which are extremely cramped. You soon learn to flick the sheet either side of the dagger board. It works very well.

 

Boatmik :

Can you add a little about what did not work on these little scows ?

I`m fascinated by how well simple scows can often sail so well.
I know this is somewhat of a "black art " ( boat design , and a huge subject
in general , but do you think some of the design elements of the PDR and OZ racer could be introduced to larger scows ?

 

Man this thread never dies! =)

Just a little update - I ended up building a summer breeze, and was very happy with it. Sadly, about a month after it was finished, there was a big storm, and while sitting in my yard on the trailer, it was crushed by a giant fallen tree limb (I'll post up a pic of the carnage sometime). I did have the pleasure of sailing her once before her untimely death and it was awesome! It was really the first (and so far only) time I've had any kind of success sailing (one or two attempts with a sunfish in doldrums). I couldn't believe how fast I got going with my first attempt at a rig and having never sailed before.

I used a tyvec spritsail I made (which fortunately survived the crash, so the rig may sail again), with a leeboard hung over the side on a rope (suggested by bataan in a different thread). I ended up running the sheet to the rudder, but I'm such a n00b and my rig wasn't exactly tuned for perfomance so I can't imagine I'd have even noticed the difference. The sprit was way to short and there was much flopping and twisting going on. Nonetheless, in probably 5-10 knots I was able to get that little boat moving pretty well.

I think my next build (once I get up the heart to try again) will probably be a pd racer type deal. I'd never done fiberglass/epoxy before and was really turned off by it. Also I don't think I could do another summer breeze (with or without fiberglass), it'd be like making a doll that looks like your dead dog because you miss it so much.

 

keep building...once you start you can not stop. I have built 14 small boats (and have owned 18), I finish one and am already thinking about what I want to try on the next one, even before I get my current project in the water. To keep them from accumulating on my property I usually give them away after I am finished playing with them. Neighborhood kids are always thrilled to have their own vessel that they can command, and it is a lot healthier activity than what their friends might lure them into.

 

Thar she blows

 

What a shame! Hope you can do it again.....Best of luck....