My cx 25

Power Boats only. Please include the boat type in your question.
User avatar
OrangeQuest
Very Active Poster
Very Active Poster
Posts: 3944
Joined: Tue Aug 28, 2018 1:14 pm
Location: Houston, Texas

Re: My cx 25

Post by OrangeQuest »

Great to see updates on your big build! Great work!
"that it isn't just an ordinary sort of boat. Sometimes it's a Boat, and sometimes it's more of an Accident. It all depends." "Depends on what?" "On whether I'm on the top of it or underneath it."
A. A. Milne

Eric1
Very Active Poster
Very Active Poster
Posts: 3072
Joined: Tue Aug 19, 2014 3:17 pm
Location: Spartanburg,S.C.

Re: My cx 25

Post by Eric1 »

Great Picture Danilo! The build is looking really nice.
I would raise the floor for the tanks. It should not be an issue.

joe2700
Very Active Poster
Very Active Poster
Posts: 629
Joined: Fri Nov 25, 2016 3:16 pm
Location: Massachusetts

Re: My cx 25

Post by joe2700 »

If those tanks are polyethylene they will expand 2-3% of their size over the first month they have fuel in them. Make sure you have room for that between the stringer or it could damage the tanks or the stringers.

dalnilo
Active Poster
Active Poster
Posts: 204
Joined: Tue Sep 06, 2011 8:51 am
Location: sicilia

Re: My cx 25

Post by dalnilo »

thb wrote: Thu Sep 13, 2018 8:50 am Danilo,

I think I would keep the tanks totally separate so you can fill each one individually and adjust your cg depending on your fuel load. You can have a fuel feed 3 way valve which you can switch which tank is feeding the engine.

Other option is to turn tanks around so that fill and vent fittings are near each other and get a 1-1/2 inch brass Y or T fitting to connect them.

If tank fittings are higher than stringers you have other issue you need to solve to raise the sole in this area.

Regards
Tom
thanks for the advices.
I think tanks connect them in a single shipment, so I install less pipes.
as regards the boarding connection, I resolve by raising the floor by three cm.

dalnilo
Active Poster
Active Poster
Posts: 204
Joined: Tue Sep 06, 2011 8:51 am
Location: sicilia

Re: My cx 25

Post by dalnilo »

OrangeQuest wrote: Thu Sep 13, 2018 8:55 am Great to see updates on your big build! Great work!
👍👍👍👍

dalnilo
Active Poster
Active Poster
Posts: 204
Joined: Tue Sep 06, 2011 8:51 am
Location: sicilia

Re: My cx 25

Post by dalnilo »

Eric1 wrote: Thu Sep 13, 2018 9:00 am Great Picture Danilo! The build is looking really nice.
I would raise the floor for the tanks. It should not be an issue.
👍👍👍👍

dalnilo
Active Poster
Active Poster
Posts: 204
Joined: Tue Sep 06, 2011 8:51 am
Location: sicilia

Re: My cx 25

Post by dalnilo »

joe2700 wrote: Thu Sep 13, 2018 9:57 am If those tanks are polyethylene they will expand 2-3% of their size over the first month they have fuel in them. Make sure you have room for that between the stringer or it could damage the tanks or the stringers.
I'm sorry but if I put foam all around, I would have the same problem?

joe2700
Very Active Poster
Very Active Poster
Posts: 629
Joined: Fri Nov 25, 2016 3:16 pm
Location: Massachusetts

Re: My cx 25

Post by joe2700 »


I'm sorry but if I put foam all around, I would have the same problem?
You can't foam around polyethylene tanks for that reason.

Example instructions: https://www.jamestowndistributors.com/u ... docId=1025
IMPORTANT: Do not use foam to secure tank in place. Resin fuel tanks require a multidimensional expansion area of 2.3% at all times; foaming a tank in place removes the chance for hydrocarbon expansion and will void tank warranty.

User avatar
Jaysen
* Bateau Builder *
* Bateau Builder *
Posts: 6499
Joined: Wed Aug 05, 2015 7:59 am
Location: St Helena Island, SC
Contact:

Re: My cx 25

Post by Jaysen »

joe2700 wrote: Thu Sep 13, 2018 1:18 pm

I'm sorry but if I put foam all around, I would have the same problem?
You can't foam around polyethylene tanks for that reason.

Example instructions: https://www.jamestowndistributors.com/u ... docId=1025
IMPORTANT: Do not use foam to secure tank in place. Resin fuel tanks require a multidimensional expansion area of 2.3% at all times; foaming a tank in place removes the chance for hydrocarbon expansion and will void tank warranty.
Does that mean that actual tank capacity is variable? EX if you have a half full tank, the tank may expand inward making the "empty" portion less than the actual volume of 1/2 the tank capacity.

Or would that only happen if the tank was restricted from expansion?

Thanks.
My already completed 'Lil Bit'. A Martens Goosen V12 set up to sail me to the fishing holes.
Currently working on making a Helms 24 our coastal cruiser.
“Mark Twain/Samuel Clemens” wrote:Eat a live frog first thing in the morning and nothing worse will happen to you the rest of the day.
Jaysen wrote: Mon Apr 29, 2019 3:44 pm I tried to say something but God thought I was wrong and filled my mouth with saltwater. I kept my pie hole shut after that.

joe2700
Very Active Poster
Very Active Poster
Posts: 629
Joined: Fri Nov 25, 2016 3:16 pm
Location: Massachusetts

Re: My cx 25

Post by joe2700 »

Jaysen wrote: Thu Sep 13, 2018 1:27 pm
Does that mean that actual tank capacity is variable? EX if you have a half full tank, the tank may expand inward making the "empty" portion less than the actual volume of 1/2 the tank capacity.

Or would that only happen if the tank was restricted from expansion?

Thanks.
I'm under the impression it's kind of a one time thing, and that once it's grown over that first month it will basically stay expanded, unless maybe you let it completely air out for a long time. I think if you restrict it from expanding outwards like its supposed to it may deform. All this is conjecture on my part though. Just what I've gathered from the manufacturers instructions and Boatowners Mechanical and Electrical Manual which I kind of consider the bible of marine systems.

Post Reply

Who is online

Users browsing this forum: Ahrefs [Bot] and 6 guests