Thrust board replacement

dizzyspots · 23 May 2015, 15:13

1981 mk2 C: wood floor is in generally good shape...but the glued in thrust board was toast. The board is out and available as a template. Any tips on re installing the board...Thinking I need to cut ney hypalon sections to add mounts to the tubes???

dizzyspots · 27 May 2015, 02:44

bump?

Projectile · 27 May 2015, 12:09

I don't know much about this, but I can tell you that the position and tension on that thrust board will be very important because when the floorboards are in place up against the resistance that the thrust board provides, they stretch out the fabric on the bottom of the boat giving the hull its proper shape (along with proper keel inflation). If that doesn't happen - if the floor isn't stretched out enough with enough tension, the hull can get a hook in it causing horrible, nose down performance with acceleration.

dizzyspots · 27 May 2015, 12:48

Good morning Projectile,
Thank you for that info. That helps.
Cheers
Mike

The Gurnard · 27 May 2015, 17:16

Do you have any photos dizzyspots ..it may help others with what you are asking about. ?

Perhaps you got few answers initially because of the term "Thrust Board" ?

I have three SIBS but no idea what one is..perhaps its just a different term for the wooden Transom ? If it is..then perhaps others can offer some advice. ?

I sincerely hope you find what you need .. regardless of my ignorance of what a thrust board is

office888 · 27 May 2015, 17:26

Quote:

Originally Posted by The Gurnard

sincerely hope you find what you need .. regardless of my ignorance of what a thrust board is

See the board to towards the bow? It is glued in place. That is a thrust board. They often rot due to being left in the trailer with water inside the boat, or they just simply come unglued over time.

dizzyspots · 27 May 2015, 17:56

Thanks 888..that is exactly what I need help on...I can see where it would be critical for forming a proper inflatable keel. ...I have the old rotten board to use as a pattern....plan is to glue a new board in place with tubes inflated....then reinstall the floor...am I on the right track??

office888 · 27 May 2015, 18:17

Quote:

Originally Posted by dizzyspots

Thanks 888..that is exactly what I need help on...I can see where it would be critical for forming a proper inflatable keel. ...I have the old rotten board to use as a pattern....plan is to glue a new board in place with tubes inflated....then reinstall the floor...am I on the right track??

You completely are!

The floor needs to be unglued to properly install the thrustboard.

REPLACEMENT MUST BE EXACT TO THE ORIGINAL.

Too far forward or too far backward will alter the floorboard stretch (referred to as "GRIP" by Zodiac). The tolerance for this is about +/- 15mm, depending on which model boat it is.

The Gurnard · 27 May 2015, 18:28

Thanks for the info on the thrust board guys.. I see what it is now.. my inflatable dont have them. It was worth asking too..as you got a good response to your question dizzyspots

Northern Pike · 27 May 2015, 19:10

I had a 1980s Mark 2C, and it didn't have a board like that.

office888 · 27 May 2015, 22:53

Quote:

Originally Posted by Northern Pike

I had a 1980s Mark 2C, and it didn't have a board like that.

Which?

There a lot of them with varying features. Futura, Virage, Tour.S, Touring, GT... Not to mention, there were about 5-6 model revisions thanks to increases in technology between 1980-1990.

With that being said, thrustboards are pretty obsolete technology...they do hold up better though in rough seas though. There's less of a chance of a floor panel being knocked free.

But then again, who has actually taken their SIB on 2 to 3 meter swells before?

dizzyspots · 28 May 2015, 01:05

my thrust board is already out ...courtesy of the rot and prior owner. Im cleaning the old glue(s) off the prior repair areas in preparation to reattaching the floor..seems like the thrust board attachment points are pretty well defined...not sure how accurate the width needs to be...

dizzyspots · 29 May 2015, 18:59

Got a tremendous amount of information from the tech dept at Zodiac USA thank you Sir!!

dizzyspots · 12 August 2015, 21:53

ready to fabricate new thrust board..I have old board for template...seems lightweight wood for being 3/4 in thick. any ideas what kind of wood it is..(its not multiply) or a suitable replacement

McNish · 12 August 2015, 22:40

I think it's Ash.

cgoing · 13 August 2015, 04:15

Some of them were mahogany

AJGentile · 03 August 2021, 01:21

Hi Dizzy, I realize you did this thruster board remount for years ago. I just bought a 1983 Grand Raid MK2 The thruster board is being held in place with gorilla tape. do you have any pictures of how you re-glued the board in place.I plan to use new piece of marine plywood laminated in fiberglass and coated in expoxy.
thank