Seeking a measurement...

[nelvar]

My SIB should be arriving in the next couple of days.

It is a Quicksilver 420 HD and comes without seats.

I have acquired the necessary bench seat patches, but am not sure where the most rearward bench should be positioned. I don’t want to put it either too near or too far from the transom.

My question to anyone with a tape measure and a SIB that is currently inflated is therefore...

“What is the measurement on your SIB between the transom and the rear of your bench seat?”


Bonus question ... has anyone used marine ply for their bench seats? If so what thickness do you recommend? (I accept their is a trade off between weight and rigidity)

Many Thanks
Dave

[Fenlander]

Personally if going to the trouble of a second seat I'd not go fixing mount patches in a position related to someone else's boat. How distanced you sit to the tiller is an individual thing.

Before getting the glue out I'd trial a seat position that suits you once you have the boat inflated by sitting on a box or something in different positions.

Re thickness I always think most OE seats are under sized apart from the Honwave ply/grp sandwich construction which is over 30mm thick.

My Aerotec seat is 21mm which is just OK as it's a narrow SIB hence a shorter span than you'll be dealing with so I'd say 24mm or more for your seat.

[nelvar]

Originally Posted by Fenlander

Personally if going to the trouble of a second seat I'd not go fixing mount patches in a position related to someone else's boat. How distanced you sit to the tiller is an individual thing.

Before getting the glue out I'd trial a seat position that suits you once you have the boat inflated by sitting on a box or something in different positions.

Re thickness I always think most OE seats are under sized apart from the Honwave ply/grp sandwich construction which is over 30mm thick.

My Aerotec seat is 21mm which is just OK as it's a narrow SIB hence a shorter span than you'll be dealing with so I'd say 24mm or more for your seat.

Fenlander, many thanks

I will definitely go for the 25mm marine ply for the seats.


Regarding the measurement from transom to seat, I completely take your point.

However, I am new to using an outboard with a tiller, so not sure whether I would be able to judge what several hours of my left arm behind my back will feel like from 5 minutes in my back garden

For example, when pulling the tiller behind my back, should the end of the tiller brush my back or be a few inches off?

The reason I was seeking measurements, was just so I know that I am not way way off the mark and end up wishing I had bought a tiller extension or finding it uncomfortable to perform tight turns. I appreciate people will have different tiller lengths, arm lengths and shoulder heights, but ball park figures are fine

[Fenlander]

Your 4.2m with alloy floor will be less affected in trim by your position than my 3.8m air floor... particularly if you carry other folks and kit.

But for me with every SIB we've owned I've preferred sitting on the right side tube which gives a natural use (to me as I say) of the tiller in my left hand. It also means it's so much easier to look behind for faster craft bearing down and most important I can slide backwards and forward on the tube to change the boat's trim to a useful degree.

You could get something like a padded top fishing box or anything really for the first outing and trial a position??

As a matter of interest the new SIB I have on order comes with a second seat but it has that integral mounting "rail" where the seat can slide to and fro for getting it spot on... so I will give that a go and see if I like sitting on it.

[Steve509926]

I'm with Fenlander, if they are fixed position mounts I wouldn't be glueing them onto the SIB until I had a chance to fit the OB and use it on the water so that I would know the best position for them.
We are all different and like different positions. David likes to sit on the right side tube, I prefer to sit half on the right tube and half on the bench, except for when I'm going slow and then I sit fully on the bench. Also if you are mostly solo you may need to use an extension, then you would want your bench position further forward.
As for using marine ply, I wouldn't go to the expense of buying "true" marine ply. Use good quality External WBP Ply, minimum 25mm. Make sure all cut sides/ends are well sealed before varnishing (use polyurethane not with quick drying water based varnish) or better still use epoxy resin.

[Oldman2]

I saw some new plastic decking recently and thought right away...Boat seats with no prep!

[Steve509926]

Originally Posted by Oldman2

I saw some new plastic decking recently and thought right away...Boat seats with no prep!

Not sure about using composite plastic decking for a bench seat in a SIB.
The widest boards I've come across 185mm and I'm sure my arse needs a bit more than that. Also there would be a lot of deflection, more so than using the same thickness of ply. Composite decking is designed to be supported at 300mm centres and if it's not, it does bend a lot.
I could be completely wrong and composite plastic decking may be the ideal maintenance free material for a SIB bench. Guess someone has to be the first to try it Oldman2

[Oldman2]

Im too lardy for anything but a big fat tube I will get some offcuts though and see if they bond together to make seats big enough for your arse an all

[Steve509926]

Originally Posted by Oldman2

Im too lardy for anything but a big fat tube I will get some offcuts though and see if they bond together to make seats big enough for your arse an all

Another insomniac