Small Boat Forum

Welcome! Need support, you got it. Or share you ideas and experiences.

Small Boat Forum

Re: Small Boat Design Concept...

67.225.114.47

[ Follow Ups ] [ Post Followup ] [ Thread: Display All Email ] [ Small Boat Forum ]

In Reply to: Re: Small Boat Design Concept... posted by Thom V on November 21, 2003 at 18:08:56:

Smart looking boat!
Have you ever felt the lack of any sort of scuppered deck at the stern? I'm always a bit unnerved by motorboats with no real protection from the occasional, accidental, come up from behind and get ya wave, most often created when suddenly decelerating in a following sea. Though with the relatively tall height of the transom in relation to it's width, maybe that's just not a factor on this boat.

Follow Ups:

Re: Small Boat Design Concept... - Thom V 12:15:28 11/23/03 (2)
Good observation Woodpecker. Yes, in the building of this design we did raise the transom height in anticipation of this concern. We also added a Motor Well Cover that is placed on top of the well, hugging the motor skeg, when the boat is underway. However, that still leaves a decent sized hole in the transom, and in the bottom of the boat, for the outboard to �live� in the well�
So far the skiff responds quickly to oncoming waves at the transom, rising up and over even some steep 5 footers with their tops breaking a bit. We believe a number of factors contribute to this behavior. The motor weight is located AHEAD of the transom, not hung on the transom, and with the weight of boat gear and gas tank even ahead of the motor, the boats pitch motion from a stern wave is not slowed as it might be with say a heavy 4-cycle outboard hung on the transom and the attending gear -- battery, gas tank etc. -- all crowded in the stern. Also, this skiff has �trail� to the bottom transom section. That is, the max beam is forward to the center of the boat and not at the stern. This presents a smaller transom target for the wave.
And perhaps, what makes it all work better is the �trick� addition to the bottom mentioned in the first post. We have added a Port and Starboard sponson to either side (but apart) from the well. These are about 2 &1/2 inches deep, 10� wide, 6� long or so and filled with foam then glassed. In calm water the boat actually �skies� on these sponsons. The sponsons have about 65 lbs of positive buoyancy each and effectively null the motor weight.
If water does get into the boat we of course have pumps. And, 2 transom drains that can be opened if the boat can maintain some headway.
The largest �fault� with this design (aside from a rough ride at speed in a chop) does involve the same situation -- sliding down a wave bow first. The Pacific City Dory type has that turned up bow section and the corresponding bottom chine to go with it. As the boat picks up speed the bottom outside chine log is immersed and at the bottom of the wave the boat wants to �hook� or attempt to trip and broach. One must be awake at the tiller and be ready to correct and add a bit of power to climb up onto the back of the next wave. If we were to build the boat again, we would eliminate the outside chine log, with its near 90 degree angle, and cover the chine area with a few layers of class tape smoothing this hard shaped angle to a rounded surface. This would not eliminate the tendency of the design to �hook� put it would make the experience less aggressive.
- Re: Small Boat Design Concept... - Thom V 16:12:44 11/24/03 (1)
  __________Here is Falk's post above dated 11/24/03 repeated:
  "Thanks a lot for showing me your boat, it's really full of interesting features. Pushing the point of gravity down by lowering the seat-height makes me wonder if it is not getting too uncomfortable, concerning the angle your knees have to bend? on the other hand i guess it makes you feel safer and cozier to sit deep inside the hull.
  I sure like the seat-arrangement you built in the back with that combination of motor and driverseat in one block , if i got that right? Is the space right and left from that enough to sleep there?
  I thought about some folding systems to provide more variabillity to the interior.
  I know I repeat myself but because i have no long time experiences with moving parts in that surrounding, I wonder if it is longlasting enough for water and so? Especially with rails in the sides of the inner hull to mount and move things on across the boat.
  Maybe you can tell me if from your experiences something like that might work in everyday-use or rather not?"
  ______ Answer:
  Hi Falk,
  We place 2 Sport-a-Seat on the forward seat bench. This gives about 12" of rise and have had no complaints about the position of knees. Yes, being down in the boat on this forward bench seat gives much confidence when zooming along at near 40 mph...
  Yes, as stated on the previous post, one can sleep to either side of the center 'box'. We would rather sleep on the beach in our tent as the skiff can have a bit of abupt motion from wind, wake action, etc. due to it's small size and lack of any dampening.
  Falk to design some sort of moving seating, sleeping arrangement for an open small boat...??? By all means give it a go and design what you think might work! Remember the adage from the boat designer Pete Culler: "Experience starts when you begin"
  Thom V
  - Re: Small Boat Design Concept... - falk 03:53:52 11/25/03 (0)
    Right Thom!
    Think I�ve got your point. But see, I somehow have to get information to ensure myself and the professors that my ideas are not just fake for the showroom but will be working in duty and be accepted by the people who use it. That�s a major part of the whole design process, for I�ll be not building and testing it in real, due to the little time we have.
    falk

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable

You can not post to an archived thread.