Bow tank for Enterprise

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scotyot
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Bow tank for Enterprise

Post by scotyot » Thu Jun 18, 2015 8:26 pm

I am in the process of renovating a Bill Bacon Ent, (18018). It was built with a bow buoyancy bag. Does anyone have information on how to replace the bag with the more modern 'built-in tank' and hatch?
Any advice would be greatly appreciated, thanks.

sam mason
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Re: Bow tank for Enterprise

Post by sam mason » Fri Jun 19, 2015 8:09 am

The plans show the bulkhead being fitted in 2 halves split up and down the middle with a backing piece behind. I always found that the plans were inaccurate and the bulkhead was yards off when fitted. The bulkhead fits to the aft side of the second foredeck main beam. If you have the decks off this is relatively easy however if the decks and kingpost are in place its a right fiddle!! Decks off it can be done in one. Decks on....... Accurate measurement is the only way then make a cardboard template. The bulkhead is shown as being 5mm but 4 is ok. Big epoxy fillets will hold it in but make sure that all the varnish is cleaned off. Patience patience, patience is the way
Good luck
Sam

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jpa_wfsc
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Re: Bow tank for Enterprise

Post by jpa_wfsc » Fri Jun 19, 2015 9:04 pm

or stick with a bag - why do you want to add weight, water traps and complexity with a tank?
j./

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JimC
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Re: Bow tank for Enterprise

Post by JimC » Fri Jun 19, 2015 10:43 pm

jpa_wfsc wrote:or stick with a bag - why do you want to add weight, water traps and complexity with a tank?
because bags are the spawn of the devil if you're actually going to use the boat?

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jpa_wfsc
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Re: Bow tank for Enterprise

Post by jpa_wfsc » Mon Jun 22, 2015 7:45 pm

Mmmmm... no, not particularly, unless they can move about - then devilish. The best arrangement I have seen is a lattice of battens above the bag, keeping it as low in the bow as possible then when swamped, the CB case will be above water level. And the 'shelf' above the bag is a usefull storage space for picnic, spray suit or whatever.
j./

National 12 "Spider" 2523
Finn K468 'Captain Scarlet'

British Moth, 630, early 60's 'Pisces'

!!!! Not CVRDA !!!!
Comet Trio - something always ready to sail.

Michael Brigg
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Re: Bow tank for Enterprise

Post by Michael Brigg » Tue Jun 23, 2015 2:03 am

JimC wrote:
jpa_wfsc wrote:or stick with a bag - why do you want to add weight, water traps and complexity with a tank?
because bags are the spawn of the devil if you're actually going to use the boat?
As a man who sticks with bags for the sake of authenticity I have to agree they are indeed of devilish origin.

Most critically a tank does not float up when you are full of water . When this happens the water can rush into the bow and cause a nose dive / submarine effect. ("Going down the mine" I think it's called.)

Very annoying if you are enjoying a gnarly reach, in waves (on the sea) blinded by spray (Think of conditions at Bosham in 2013 when that little low pressure spike blew through on the Sunday race.

Also, when you do go under water, a tank wont shrink in response to the cold immersion. On a sunny day a Bouyancy bag can shrink in the cold by nearly half its volume with serious resulting loss of buoyancy. This is why they so often escape in a capsize if not actually completely covered or attached to lanyards/straps

Well worth the extra weight if it's what you want!
Michael Brigg

Rupert
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Re: Bow tank for Enterprise

Post by Rupert » Tue Jun 23, 2015 9:20 pm

On the other hand, I have seen tanks implode, leak, rot from the inside etc,etc. But agree bags can be a right pain.
Rupert

roger
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Re: Bow tank for Enterprise

Post by roger » Wed Jun 24, 2015 1:02 pm

If anyone wants them i have a selection of bags available.
Hornet 191 Shoestring,
Hornet 595 Demon awaiting restoration
Hornet 610 Final Fling
Hornet 353

dan214
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Re: Bow tank for Enterprise

Post by dan214 » Sun Aug 23, 2015 12:30 am

Please excuse me if this is a silly question (I am new to sailing) but is it worth putting a buoyancy bag inside the tank? My thinking is that if i where to capsize and i wasn't quick enough to right my boat, the tank may fill with water and like Michael said cause a nose dive?

Rupert
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Re: Bow tank for Enterprise

Post by Rupert » Sun Aug 23, 2015 8:17 am

Hopefully a tank won't be that leaky! Having a damp bag sitting against the wood could also cause problems. I did this in an old Firefly once for the side tanks, and they never really dried out.
Rupert

JimC
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Re: Bow tank for Enterprise

Post by JimC » Sun Aug 23, 2015 9:23 am

Well, it *can* happen, but usually only if you're capsized for a very long time and you have very bad leaks
(or an old Holt glass Enterprise which comes to the same thing). In my list of things to worry about it scores very near the bottom. And to be quite honest, since bags are very very bad at filling the total air (water?) space anyway it would probably make minimal difference. Solid glass boats usually have some foam in so that they can't actually sink, but this is best located under decks and the like where it will stay as dry as possible.

Rigman
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Re: Bow tank for Enterprise

Post by Rigman » Sun Dec 06, 2015 8:52 am

Hi, I have replaced bow tanks on 3 enterprises all GRP but the job is the same on wooden ones.
If you do not have a template, as said before you have to make one out of cardboard. Make it a very snug fit. about 15cm in front of the king post.
Cut panel out of 10mm marine ply and epoxy the back side. Best to cut a hatch out at this time. Good hand hold
I always remove the king post, mainly because its rotten at the base (water collects there)
This way you can fit the new panel in one piece. Oh yes, sand the hull and clean where the panel fits.
Place the new panel in place and mark around it with a pencil. Remove the panel and position 4 25mm square blocks 10mm inside the line on the hull sides.
Again using epoxy or strong glue. Leave to set.
Once set use epoxy on the mating face and push the new panel into place. Use masking tape to hold in position and allow to dry.
I now mask up 10mm from the edge of the panel. boat as well.
So there are two strips of masking tape. I personnel use seckaflex (not sure of spelling) and using a silicon gun squeeze the secloflex into the gap. Just like doing the edge of a bath.
Using rudder gloves I push it into the gap with my finger, leaving a smooth fillet. Take off the masking tape carefully and allow to dry over night.

I have never had a problem.
Note if you have water in the bow tank, wash out with fresh water and put in inspection lamp in there for a few days. Low heat will dry out the tank.

mph1977
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Re: Bow tank for Enterprise

Post by mph1977 » Sat Dec 26, 2015 3:09 am

bag bow tank ents are pigs if flooded

there;s basically 2 ways of retro fitting a bow tank

1 way is combined with a re-deck

the alternative the previously discussed two piece method

adding a bow tank to an ent only puts one extra 'seam' into the boat as such

bow tank and side bags was the default way of building wodden ents in later years

mph1977
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Re: Bow tank for Enterprise

Post by mph1977 » Sat Dec 26, 2015 3:12 am

dan214 wrote:Please excuse me if this is a silly question (I am new to sailing) but is it worth putting a buoyancy bag inside the tank? My thinking is that if i where to capsize and i wasn't quick enough to right my boat, the tank may fill with water and like Michael said cause a nose dive?
if the tank is fitted correctly it will not fill - it;s sealed and commercial hatches and drain plugs are watertight if fitted correctly and used properly

if reserve buoyancy is a worry pop bottles and or ping pong balls in net bags ... ( many GRP boats use closed cell foam blocks or 'air bags' for reserve buoyancy.

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