Re: Bantam 16/20

I have studied your photos - a lot of good ideas there!  I have just been working out the ply requirements for the Bantam.  With some plans Phil set out a cutting plan that was so efficient he must have spent hours arranging all the parts!  At present I have got it down to about 6 x 3mm, 18 x 6mm and 7 x 12mm, but that doesn't include the window frames etc. There seem to be as many ways to close in the house as there are Bantams built. 
Brent (Tasmania).
Oh Yeah, one more thing! You can get some idea of my steering station in the photos in Bolger group 6, Bantam - Drifter.
Bob

HI,
I too imbedded lighting wiring in the cabin top foam. Before I laminated the plywood top skin in place I took measurements and made a blueprint of where they are.  Instead of running them down the middle I ran them to one side, then over at the front for running lights. The reason I did both of these things is because I had thought that maybe someday I might want to put a hatch in the top as a more efficient way to ventilate heat so would need to have a clear area and know just where the wire were :)
Steering station. I did not make that rather complicated pivoting system, but I did make the whole thing removable for when needing to fold the cabin. I made the station to fit at the forward starboard side just below the hinging front window. The single lever shift/throttle is mounted separately on the side The steering station removes with two machine screws and just drop down onto the bridge deck to give the clearance needed to fold the cabin. If not building a folding cabin things get a lot easier.
Foam Really nothing that needs bending as the roof is flat and so is the bottom. If you can get thick stuff, yes, you will save a lot of epoxy and time and work.  I had to laminate 2" (your 50mm) as that was the thickest available in my area when building.
One of the biggest departures I did from the plans was to the bow sections. all those plywood cutouts stacked, then shaped, and finally covered with a layer of glass or other cloth was something I did not like. First was the time to cut out and shape the plywood, but the main thing for me was that I intended, and do, run up on beaches, and sometimes there are unseen things in the sand :o I envisioned the thin skin getting cut through and water getting into the plywood and rot starting. So instead I laminated foam in place until thick enough, then shaped the foam  leaving it a about 3/16" smaller on the main hull and 1/8" on the sponsons. I then did an epoxy, glass, kevlar layup making this just about bulletproof. There can be a lot of banging and cuts going on here when beaching, or if clunking into some flotsam, without doing any damage.
If any other questions, feel free to ask.
Bob
 

Thanks for your reply.  I have received the plans and am studying them now.
The foam cabin top looks light enough with good insulation.  I can run some lighting cables through the foam before laminating.
Bob, did you build the steering station as drawn or is yours removable please?
I have also found foam for the hull in 25mm, 50mm 100mm and 150mm and I am thinking the 100mm may bend enough and save a lot of glue.
I really like the longest version but too big to tow and store so I may just  move the outboard out and extend the floats on the 16/20.
A whole lot of potential to build the house to my liking though. Brent

Raising the cabin has never been a problem with the worm gear winch. It takes maybe two minutes to raise the roof with the two side panels attached. What takes longer is getting the side panels positioned while you then lower the roof to lock them in place. Unless the boat is level gravity keeps swinging them out of place, and even on the trailer a boat is never level :) With two people this is not a problem. One inside to push them into place while the other outside is operating the winch. Being solo most of the time I have to use a long pole to push them into place with one hand while operating the winch with the other.
I have thought once in a while that I could replace the manual worm gear winch with a 12V electric one, but it really is not hard to raise.
All that being said, what you should ask yourself is if you have a need to the folding cabin. Phil designed this for someone who needed to get the boat into a small garage.  The guy in Florida never planning on towing except down to the ramp so built a standard cabin. I built the folding cabin because I tow long distance, sometimes over two thousand miles, so wanted the lower wind resistance. If you never plan to tow long distance or need to get into a garage you can save yourself a lot of work by just building a regular cabin. Also, if in a driving rain or when getting slammed by waves in bad weather I have not been able to keep out all the water. Never had this problem with the non folding cabins, like on my Micro Trawler. While boaters may be used to some water getting in, here it is right above the setees so that my bed for the night is now wet. This however is not part of the Bolger plans so no fault there. As planned the panels have non opening plastic in them and if you want ventilation you have to fold the entire panel up. I instead put sliding windows in the panels and it is the windows that seem to leak. The front cabin door as designed does allow some water through when hit by waves, but being in such weather in this boat doesn't happen very often. I think the reason for these leaks is the door has to open inwards for the cabin to be folded, and must be made thin and light, so flexes. A non folding cabin could have the door open outwards so being hit by a wave would push it into the gasket instead of away from it.
Bob
PS - Having no need for it I did not build the take off bow section, which also makes things easier.
Thank you Susanne for the suggestion of a worm-gear winch. I haven't looked at them before and they look ideal and very safe. I have plans for your "lily" and was looking at the battery pack adjustment mechanism you designed thinking something like that would also work. B

--- Inbolger@yahoogroups.com, <philbolger@...> wrote:
>
>
> The weights involved are not overwhelming and should be manageable with a modest ‘gear-reduction’ per two blocks to allow manual lifting of all four corners simultaneously.
> Or a FULTON $80.- worm-gear winch will allow lifting all slowly but steadily, assuming you’ll run all leads to than one location.
> I’d go low-tech first...
>
> Susanne Altenburger, PB&F
>
>

The weights involved are not overwhelming and should be manageable with a modest ‘gear-reduction’ per two blocks to allow manual lifting of all four corners simultaneously. 
Or a FULTON $80.- worm-gear winch will allow lifting all slowly but steadily, assuming you’ll run all leads to than one location.
I’d go low-tech first...
 
Susanne Altenburger, PB&F
 
 
Sent:Sunday, January 26, 2014 10:59 AM
Subject:[bolger] RE: Bantam 16/20
 
 

If you have to add something complex to raise the lid, maybe something driven by the trailer winch would be a good starting point.

(assuming you will trailer it and that dropping the top on the water for mooring or bridges is not important to you)

 

 

justin

If you have to add something complex to raise the lid, maybe something driven by the trailer winch would be a good starting point.

(assuming you will trailer it and that dropping the top on the water for mooring or bridges is not important to you)



justin

We looked at such devices (linear actuators) but found the lift-distance and associated cost challenging, quite apart from certain inherent structural problems.
Hence the manual lifting provisions.

Between doing
- a foam-cored roof-panel to reduce the sun’s impact,
- the centerline doors,
- the swing-up side-windows, and
- the awning option to share the windows
‘as is’ she should serve to keep folks comfortable in summer-heat as any boat without AC...

Susanne Altenburger, PB&F
 
From:Brent
Sent:Sunday, January 26, 2014 1:27 AM
Subject:[bolger] Re: Bantam 16/20
 
 

Thanks for the reply. Yes, we get quite a bit of sun so I was wondering if the curtains would be sufficient to keep thing cool. Not often we have no wind so with the option of opening both doors etc I think we can keep cool.
Another thing I am thinking about is to use folding arms at each corner to support the roof, operated by 12v linear-actuators. Imagine how easy it would be to raise the roof with the push of a button! Not very "Bolger" but I am sure he would approve as it wouldn't be too complex to install and the Bantam is unique as it is. B

...> Another thing. Those 360 degree windows are great for views, but on a sunny day (and I know you get lots of sun down under) it can get HOT in the cabin if at anchor and no breeze. At anchor I look like a cabin as I installed awnings along the sides. Even leave them up when at displacement speeds and in really calm waters. They also allow me to keep the windows open for ventilation when it is raining Lots of people in other boats take pictures of this strange looking thing going by LOL!!

Thanks for the reply. Yes, we get quite a bit of sun so I was wondering if the curtains would be sufficient to keep thing cool. Not often we have no wind so with the option of opening both doors etc I think we can keep cool.
Another thing I am thinking about is to use folding arms at each corner to support the roof, operated by 12v linear-actuators. Imagine how easy it would be to raise the roof with the push of a button! Not very "Bolger" but I am sure he would approve as it wouldn't be too complex to install and the Bantam is unique as it is. B



...> Another thing. Those 360 degree windows are great for views, but on a sunny day (and I know you get lots of sun down under) it can get HOT in the cabin if at anchor and no breeze. At anchor I look like a cabin as I installed awnings along the sides. Even leave them up when at displacement speeds and in really calm waters. They also allow me to keep the windows open for ventilation when it is raining Lots of people in other boats take pictures of this strange looking thing going by LOL!!
???? Don't know which of us you are asking. I think the Florida one is in Bolger (the first one, no number) group photos. Mine (Minnesota) is in Bolger 6 group photos, Drifter, which includes a photo of the micro trawler I built docked with the Bantam.
3rd photo on the right (at least that is how it came up when I looked with my browser) is of it on plane. A low speed plane of 13.5 as that is the most it does with only a 25hp. It is really an 18/22 as I stretched it two feet which is probably why it really needs a 35, but the high thrust OBs (at least then and I have not bothered to check in recent years as too costly to change) were 9.9, 25, then had to go all the way to 50 which I did not want to do. The only other photos ever posted online are in a Duckworks mag article in Jan 2008. The novelty of posting pics and/or writing stories wore off :)
Bob
POWER SHARPIE
how about some details and pictures and where is it?
mike
Regarding my stretched Bantam in Florida. It does not have the built up bottom and does not seem to need it at the slower non planning speeds. She, Pelican/ has circumnavigated Florida 4 times now.
   I did build her with Phil/s scantlings which as we know are important for the weight and hence performance of the design.
    She is holding together quite well/ large radiused joints on the underhull connections but this year I am hoping to bring her north to Canada and use her on the Rideau Canal permanently as am begining to  worry about her vunerability to things like hurricanes sitting on her trailer unused for 10 months every year.
  I think the glassed in house can really extend my boating season here in the shoulder seasons.

    Heading down to central fl in a couple of weeks if enybody wants to see her in Fort Pierce/ Wether she goes north by trailer or up the intracoastal has yet to be decided. sure she is capable but time constraintsmight  decide.
      She has been around a while. To clear up.   the time line she was actualy the first hull launched as I launched her in January in Florida without the cabin. I used her in that configuration for several months while I built the windows and cabin top which took about as long and cost more i think than the hulls. All that plexi and eletric systems etc.So I believe that makes her the second completed boat.
     I talked with Phil and lengthed the hull 6 feet and the cabin 4 feet the next year. A big improvement with 26 foot waterline and no transom drag. Very effecient. A delightful boat. Hope to get much more use from her.
     Still have my 32 foot power sharpie for sail and have had a few, 10, calls but mainly from inappropriate places and have to tell them I thinkt would be best on sheltered waters. No serious interest despite a year of advertising and she  is sitting on a $3/000 aaluminum tandem axle trailer. I think she may be cut up this summer for a bunkie as I can,t get $5,000 for her. Something to think about if you are thinking of building a big boat which requires many hours of labour.
             regards john bartlett

Not currently building, but built and own what was the third one done. After reading about the problems with the first one by Tom David and the subsequent upgrade to get more bridge clearance I built the double bottom.  Thinking like you I wondered why build the original way and then add on. Seeing as how I had to wait for summer to start I wrote to Phil and asked him.  To my surprise he wrote back recommending that I not do that. He said it would be better to build as original, then add.

Perhaps he felt it added strength to a hull of that size built with only 6mm ply where the overlap is like a lapstrake or clinker build, plus the original bottom now acting as a full support to keep those 6mm sides from oil canning. I can tell you that built the way he advised that I have been in seas taking waves right over the bows with no problems in a boat that was meant for protected waters. Well, no problem for the boat. Never too enjoyable for the people :) I had previously built a Micro Trawler and can tell you the Bantam is WAY kinder in rougher water! I can also tell you that with the added weight it would really only plane with the 25 Yamaho high thrust if empty of cruising stores, just gas and one or two people. The guy (can't think of his name) in Florida who built the second one only wanted displacement speeds and lengthened it adding rocker to the stern and runs it with a 9.9 Yamaha high thrust. He says he get 18mpg at 6 mph with that setup.  I only get about 7.5 with the 25, so you might want to think about that.

Another thing.  Those 360 degree windows are great for views, but on a sunny day (and I know you get lots of sun down under) it can get HOT in the cabin if at anchor and no breeze. At anchor I look like a cabin as I installed awnings along the sides. Even leave them up when at displacement speeds and in really calm waters. They also allow me to keep the windows open for ventilation when it is raining Lots of people in other boats take pictures of this strange looking thing going by LOL!!

Have fun with the build!

Bob


Bob





---In bolger@yahoogroups.com, <brent.kennedy@...> wrote:

Hi all. I am wondering if anyone is building a Bolger Bantam at the moment.

The deeper hulls seem a good idea, but I think I would use foam on the main hull bottom only and try and build the "amas" deeper from scratch to save the "retrofit problems".

I was out in the sun the other day (southern hemisphere summer!) thinking the full standing headroom and weather protection of the Bantam would be wonderful.

Just thinking of jumping in and buying the plans before the Aussie dollar drops through the floor!

Brent (Tasmania)
Hi all. I am wondering if anyone is building a Bolger Bantam at the moment.

The deeper hulls seem a good idea, but I think I would use foam on the main hull bottom only and try and build the "amas" deeper from scratch to save the "retrofit problems".

I was out in the sun the other day (southern hemisphere summer!) thinking the full standing headroom and weather protection of the Bantam would be wonderful.

Just thinking of jumping in and buying the plans before the Aussie dollar drops through the floor!

Brent (Tasmania)