I am sailing an F18HT in central Florida and we can see the need to lift the rear crossbeam. I am looking for info about this and any other mods that can improve the performance of this boat

Thanks

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Flightlead Bimare F18 HT SpaceCoast
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Can you put spacers between the crossbar and hull until you achieve the performance you're looking for and then fill the crossbar saddle with the appropriate resin and fiber. You might need longer bolts.

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'82 Super Cat 15
Hull #315
Virginia
Previously owned: '70 H14, '79 H16, '68 Sailmaster 26, '85 H14T
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flightlead

we can see the need to lift the rear crossbeam.

The crossbeam is an integral part of the cat's frame, and blends forces from the mast, hulls and trampoline. Changing it's geometry is messing with physics and structural integrity.
Are you sure you're smarter than the designer?

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Sheet In!
Bob
_/)_____/)_/)____/)____/)_____/)/)__________/)__
Prindle 18-2 #244 "Wakizashi"
Prindle 16 #3690 "Pegasus" Sold (sigh)
AZ Multihull Fleet 42 member
(Way) Past Commodore of Prindle Fleet 14
Arizona, USA
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klozhald

flightlead

we can see the need to lift the rear crossbeam.

The crossbeam is an integral part of the cat's frame, and blends forces from the mast, hulls and trampoline. Changing it's geometry is messing with physics and structural integrity.
Are you sure you're smarter than the designer?

Point taken! I still need info on the lift and other performance mods that are available for this particular boat.

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Flightlead Bimare F18 HT SpaceCoast
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Another great boat that joined the Dead Boat Society. Somewhere here or on Catsailor is a 10 year old thread about the mod. Maybe try Lars Guck.

http://www.guckinc.com

While I agree with klozhald's comment in general, every 18HT I've ever seen in person had the rear beam raised to mitigate beam slap. Most were modified like JoPo's in this vid:
https://www.youtube.com/watch?v=2czD8xQkpAM
It's mounted on top of sections of the same beam extrusion somehow. Not sure how it's welded/bolted or how tramp attachment is handled.

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Jerome Vaughan
Hobie 16
Clinton, Mississippi
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There’s currently one of these boats for sale in the classifieds on this site. Based on the pictures, it looks like they probably shaped a riser out of foam and then glassed it into the hull. Maybe you could contact the seller directly to see if they can provide more details.

sm

klozhald

flightlead

we can see the need to lift the rear crossbeam.

The crossbeam is an integral part of the cat's frame, and blends forces from the mast, hulls and trampoline. Changing it's geometry is messing with physics and structural integrity.
Are you sure you're smarter than the designer?

Normally that's the case, but evidently the designer bit the big one on the 18HT rear beam design. They all seem to be modified one way or another to raise the rear beam.

So flightlead it's not your imagination.

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Damon Linkous
1992 Hobie 18
Memphis, TN

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Thanks for your input everybody

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Flightlead Bimare F18 HT SpaceCoast
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Flightless. I own a ht..if I can help..give me a call 2 five one 648 2 four 4 9

DamonLinkous

klozhald

flightlead

we can see the need to lift the rear crossbeam.

The crossbeam is an integral part of the cat's frame, and blends forces from the mast, hulls and trampoline. Changing it's geometry is messing with physics and structural integrity.
Are you sure you're smarter than the designer?

Normally that's the case, but evidently the designer bit the big one on the 18HT rear beam design. They all seem to be modified one way or another to raise the rear beam.

So flightlead it's not your imagination.

flightlead- it turns out you ARE smarter than the designer!
Strong work!

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Sheet In!
Bob
_/)_____/)_/)____/)____/)_____/)/)__________/)__
Prindle 18-2 #244 "Wakizashi"
Prindle 16 #3690 "Pegasus" Sold (sigh)
AZ Multihull Fleet 42 member
(Way) Past Commodore of Prindle Fleet 14
Arizona, USA
--

flightlead:
I've uploaded this image to the Beachcats Technical Album (https://www.thebeachcats.…ictures?g2_itemId=131055):



It's a friend's Bimare F18HT, but he didn't build the beam mod....it came off another boat. As I understand it, the previous owner of the beam had it fabbed, but I don't know if it was his design or from some other source.

Hopefully this will give you some ideas for your solution.

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Jerome Vaughan
Hobie 16
Clinton, Mississippi
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rattlenhum

flightlead:
I've uploaded this image to the Beachcats Technical Album (https://www.thebeachcats.…ictures?g2_itemId=131055):



It's a friend's Bimare F18HT, but he didn't build the beam mod....it came off another boat. As I understand it, the previous owner of the beam had it fabbed, but I don't know if it was his design or from some other source.

Hopefully this will give you some ideas for your solution.

thanks Rattlehum

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Flightlead Bimare F18 HT SpaceCoast
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I have since had this boat out in high winds and large chop. I was amazed how the hulls effortlessly sliced through the waves with no resistance but when the rear beam slaps, it will knock you off the boat as you go flying forward. We definitely need a suicide line for that until we get the lift kit....

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Flightlead Bimare F18 HT SpaceCoast
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