Re: [bolger] new subscriber/ electric auxiliary
In a message dated 5/14/00 5:20:54 PM Central Daylight Time,
dewhurst@...writes:
<< A bonus: Euler theory can be applied more easily to a bipod than to a
traditional mast! >>
I have a dim recollection of reading a Euler formula for failure of a column
in compression - diameter v. height being the critical variables, if I recall
correctly. However, it seems to me that an un-stayed mast, to take a
particular case (not without relevance to "Bolger boxes"), is more akin to a
cantilevered beam than a column in compression. Anyway, the Euler formula
did make me wonder (I'm too innumerate do do any calculations) about the use
of "diaphragms" in a hollow mast as a way of "cheating'' the height variable.
Do you think this is an idea worth pursuing? Anyway, the notion that a
bi-pod mast yields to a simplified Euler analysis boggles my mind! I do hope
that you will continue this thread for my benefit.
Ciao for Niao,
Bill in MN
dewhurst@...writes:
<< A bonus: Euler theory can be applied more easily to a bipod than to a
traditional mast! >>
I have a dim recollection of reading a Euler formula for failure of a column
in compression - diameter v. height being the critical variables, if I recall
correctly. However, it seems to me that an un-stayed mast, to take a
particular case (not without relevance to "Bolger boxes"), is more akin to a
cantilevered beam than a column in compression. Anyway, the Euler formula
did make me wonder (I'm too innumerate do do any calculations) about the use
of "diaphragms" in a hollow mast as a way of "cheating'' the height variable.
Do you think this is an idea worth pursuing? Anyway, the notion that a
bi-pod mast yields to a simplified Euler analysis boggles my mind! I do hope
that you will continue this thread for my benefit.
Ciao for Niao,
Bill in MN
At 18:34 13/05/00 EDT, you wrote:
Initially it was to be 8 metres long and just under 2.5 metres wide. The
trailerable width limit here is 2.5 metres before special permits are
required and the all-up weight 2000 kilograms before an independent braking
system is required. I suggest that you consider your trailer rules
carefully before you decide on the size of the boat.
If the boat has a flat bottom, as I though of first, and you want to
maximize the beam, you will have to put all the hull above the wheels. Then
you have problems getting the boat on and off the trailer. If you have
about 15 degrees of deadrise you have a harder boat to build but it will sit
much lower on the trailer.
For stability an 8 metre boat is going to go well over the 2000 kg limit on
the trailer, probably over it! I thought that I could get around that with
water ballast. That is probably feasible but there is a lot more design and
much more complexity.
I have moved away from the original concept towards a 6 metre hull with 15
degree deadrise aft and a warped bottom increasing the deadrise forward.
With internal fixed ballast this boat should displace about a tonne. With a
bow transom, leeboards and a bipod mast space inside can be maximized. The
hull will look a bit like a cross between a Dutch punter and a Chinese junk!
A bonus: Euler theory can be applied more easily to a bipod than to a
traditional mast!
Roger.
>In a message dated 5/13/00 1:03:29 AM Central Daylight Time,I started off with the idea of building a trailerable motor sailer houseboat.
>cinetics@...writes:
>
><< My dream project is to build an electric auxiliary trailerable
> coastal cruiser/ gunkholer. The concept is a 24ft lwl 26-28ft loa
> hull displacing 4500-6000lbs. All up trailer weight not to exceed
> 6000lbs. >>
Initially it was to be 8 metres long and just under 2.5 metres wide. The
trailerable width limit here is 2.5 metres before special permits are
required and the all-up weight 2000 kilograms before an independent braking
system is required. I suggest that you consider your trailer rules
carefully before you decide on the size of the boat.
If the boat has a flat bottom, as I though of first, and you want to
maximize the beam, you will have to put all the hull above the wheels. Then
you have problems getting the boat on and off the trailer. If you have
about 15 degrees of deadrise you have a harder boat to build but it will sit
much lower on the trailer.
For stability an 8 metre boat is going to go well over the 2000 kg limit on
the trailer, probably over it! I thought that I could get around that with
water ballast. That is probably feasible but there is a lot more design and
much more complexity.
I have moved away from the original concept towards a 6 metre hull with 15
degree deadrise aft and a warped bottom increasing the deadrise forward.
With internal fixed ballast this boat should displace about a tonne. With a
bow transom, leeboards and a bipod mast space inside can be maximized. The
hull will look a bit like a cross between a Dutch punter and a Chinese junk!
A bonus: Euler theory can be applied more easily to a bipod than to a
traditional mast!
Roger.
In a message dated 5/13/00 1:03:29 AM Central Daylight Time,
cinetics@...writes:
<< My dream project is to build an electric auxiliary trailerable
coastal cruiser/ gunkholer. The concept is a 24ft lwl 26-28ft loa
hull displacing 4500-6000lbs. All up trailer weight not to exceed
6000lbs. >>
Welcome to the group! You certainly seem confident in your calculations. I
hope this is the start of a long, interesting thread. The notion of elecrical
auxilary power for a sailboat seems an odd notion to me, but it certainly set
off a thread in this group very recently. I can imagine the charm of an
electric launch in suitable conditions - perferably one where bass boats, jet
skis and boom boxes are prohibited. Given the weight of lead-acid battery
energy storage and the fact that speed and "trailability" seem to be in some
inverse proportion to displacement, and cost in some direct proportion to
displacement, I wonder whether an attractive compromise solution exists.
6000# + a box keel does not sound very "trailerable" to me. A recent issue of
MAIB had an article by Bolger, HIMSELF, about using an electric winch
temporarily attached to a small car to haul a very substantial boat, so I
can't say the concept is unfeasible. Still, the first impression that
springs to my mind is that you would need a Chevy Suburban 4X4 to haul the
thing from Travel-Lift to Travel-Lift. Mind you, I speak from zero experience
- my trailering experience includes nothing larger than some older 16' - 18'
inboard runabouts. Launching and retrieving those from typical DNR
maintained lake access in MN requires some judgement as to which access to
use, at what water level, and what vehicle to use.
Ciao for Niao,
Bill in MN - Hot stock tip!!! - (If there weren't enough indications that we
are in the classic phases of a speculative bubble) - the MPLS Stribune's
hunting-and-fishing reporter says that a disappointing walleye fishing opener
in MN ( i.e. Mommys' Day Hallmark Holiday) correlates with a rising stock
market for the remainder of the year.
cinetics@...writes:
<< My dream project is to build an electric auxiliary trailerable
coastal cruiser/ gunkholer. The concept is a 24ft lwl 26-28ft loa
hull displacing 4500-6000lbs. All up trailer weight not to exceed
6000lbs. >>
Welcome to the group! You certainly seem confident in your calculations. I
hope this is the start of a long, interesting thread. The notion of elecrical
auxilary power for a sailboat seems an odd notion to me, but it certainly set
off a thread in this group very recently. I can imagine the charm of an
electric launch in suitable conditions - perferably one where bass boats, jet
skis and boom boxes are prohibited. Given the weight of lead-acid battery
energy storage and the fact that speed and "trailability" seem to be in some
inverse proportion to displacement, and cost in some direct proportion to
displacement, I wonder whether an attractive compromise solution exists.
6000# + a box keel does not sound very "trailerable" to me. A recent issue of
MAIB had an article by Bolger, HIMSELF, about using an electric winch
temporarily attached to a small car to haul a very substantial boat, so I
can't say the concept is unfeasible. Still, the first impression that
springs to my mind is that you would need a Chevy Suburban 4X4 to haul the
thing from Travel-Lift to Travel-Lift. Mind you, I speak from zero experience
- my trailering experience includes nothing larger than some older 16' - 18'
inboard runabouts. Launching and retrieving those from typical DNR
maintained lake access in MN requires some judgement as to which access to
use, at what water level, and what vehicle to use.
Ciao for Niao,
Bill in MN - Hot stock tip!!! - (If there weren't enough indications that we
are in the classic phases of a speculative bubble) - the MPLS Stribune's
hunting-and-fishing reporter says that a disappointing walleye fishing opener
in MN ( i.e. Mommys' Day Hallmark Holiday) correlates with a rising stock
market for the remainder of the year.