2000 130 SPORT Bench Seat Re-fit

[itsmemagic]

Q1: on a 2000 130 SPORT how can the base for the seats be lowered so that Tempress NaviStyle High-Back bucket seats can be installed at a proper height for comfortable seating?

Fig. 1. The seat base for the OEM seat on the 130 SPORT is molded into the hull line. In this view, the OEM seat has been removed.

portSeatBaseMoldedinHullLiner.jpg (47.88 KiB) Viewed 367 times

Fig. 2. Another view of the OEM seat base molded into the hull.

moldedSeatBase.jpg (22.81 KiB) Viewed 367 times

Fig. 3. This battery and battery box will be replaced with a lower-profile battery.

batteryLocation.jpg (42.16 KiB) Viewed 367 times

BACKSTORY

I'm removing the original bench seating with backrest in my 2000 130 SPORT and installing Tempress bucket seats on a teak plank.

Locating these new seats on top of [the existing molded-in seat bases in the hull liner inwale ] will result in a seating height too high for comfortable steering and throttle access, largely due to the higher Tempress seat height and padding.

I'm thinking of mounting piece of wood (about 1.5-inch wide) [onto the existing molded-in seat bases on the inwales of the hull liner to create a cleat for mounting the new teak plank onto which I will mount the new seats] creating a new and lower the bench and achieve a better height.

Fitting the battery in the original location will not be a problem as I will use a smaller form-factor battery like the NOCO NLP20.

Any advice will be much appreciated.

The photographs can also be seen at these URLs:
https://photos.app.goo.gl/eekEQ3HuaSYkV9Ev6
https://photos.app.goo.gl/foqoZH2LZY5cB9xFA
https://photos.app.goo.gl/3uWb6Ptqo8nn6CbD6

[Moderator's note: I have created in-line images as illustrations to better explain the plan for the new seats and rewritten parts of the narrative to clarify the terminology used.]

[jimh]

I suggest that to create a really solid base for the new teak plank, use a board of the same width as the teak plank, and create a riser from the cockpit deck level to the desired new (lower) level for the teak plank to sit on. The riser board will transfer the load of the new plank, the new seats, and the weight of the people onto the cockpit deck. And here I am hoping there will be some embedded reinforcement under the deck lamination at that location to spread the load over more area of the cockpit deck and avoid damaging the laminate layers.

Q2: do you have the embedded reinforcement location diagram for this 130 SPORT?

If so please give the URL for it.

To fasten the riser boards to the hull liner inwales, you need to look at the location of any embedded reinforcement in the hull in that area. Unless there is an appropriately strong and thick embedded reinforcement location below the lamination layers of those OEM seat bases on the cockpit inwales, you would not be likely to attach a cleat to hold the teak plank and have sufficient strength to carry the total weight of the plank, the seats, and the people, particularly considering the shock loading that will occur when the boat is operated in rough seas.

Another problem to consider:

Q3: can you remove the residual adhesive that was holding the seat base to the molded-in support bases?

Leaving the adhesive in place will create a rather ugly appearance of the modification.

Another approach would be to use some aluminum angle stock to create a sort of Z-bracket, resting atop the original mounting base, then extending downward several inches to the desired height of the teak plank. Or you could laminate your own Z-bracket using carbon fiber and epoxy resin. The Z-bracket would carry the load of the teak plank, the seats, and occupants and put it back onto the original seat base.

[jimh]

As a general rule, when you make a modification to a Boston Whaler boat, such as this big change in the seating that you are planning, a good approach is to make it possible to undo the modification in the future. I mention this because at some point you may want to sell the 130 SPORT and get a bigger boat. Selling any boat with a big modification from OEM condition may cause some reduction in the number of interested buyers, but if the modification can easily be undone, that drawback disappears.

[itsmemagic]

Thanks so much for the detailed and thoughtful response—that's incredibly helpful advice and exactly the kind of insight I was hoping for.

You've hit on my main concern regarding load transfer. I don't have the embedded reinforcement location diagram for the 130 SPORT. Is there generally a good way to find such diagrams for older models, or are they quite rare? I'll definitely be looking closely at the hull liner in that area once the original bench is out.

Regarding the adhesive: I actually started on that yesterday with acetone, and it's going fairly well. However, it looks like there are some deeper scarring in the fiberglass, ~2mm deep, from how the previous bench was installed. I'm guessing this bench might not have been original to the boat.

I really appreciate your suggestions for creating a solid base:

The idea of a riser board from the cockpit deck level is an interesting alternative. I hadn't considered transferring the load all the way down to the deck like that, but it makes a lot of sense for spreading the load. I'll need to visualize how that would integrate with the existing molded inwales.
The aluminum angle stock or laminated Z-bracket also sounds like a very practical approach to put the load back onto the original seat base, perhaps in a more structurally sound way than just drilling a wood cleat.

I've also changed my mind and purchased two 6.5" wide Sapele wood boards instead of teak for a fraction of the cost (8%) and will be installing them together with a small gap for water runoff in the middle.

And yes, the advice about making the modification reversible is a very wise point for future resale value. I'll keep that in mind during the design process.

[jimh]

Re: locating the wood locating diagram

Boston Whaler maintains many documents on-line. The starting point is a bit hard to find. Begin at the EXPLORE menu on the top page of the wesbite.

https://www.bostonwhaler.com/

Under EXPLORE on the left under the heading WHALER OWNERSHIP find

RESOURCES and MAINTENANCE
https://www.bostonwhaler.com/resources- ... nance.html

Then scroll down a bit to a search form entry section under OWNER DOCUMENTS. Enter the desired parameters for YEAR, FAMILY, MODEL and DOCUMENT TYPE.

I browsed several different models, and the best wood locating diagram (and only one) I could find was for a 1999 130 SPORT. I would expect that would be applicable to your boat. Here is a direct link:

https://www.bostonwhaler.com/content/da ... s-1999.pdf

The drawing shows that there is embedded material in the seat support base for the helm seat on Starboard side, identified as "78-J897-03" and in the table under the heading LEGEND that material is described at "03" as "3/8" PHENOLIC (4) 1: x 12". The "4" in parenthesis indicates four pieces are used in the boat, and the assumption is one piece in each of the four seat bases.

This is very good news. The use of phenolic material at 3/8-inch thickness means you could probably (and very carefully) drill and tap that material for a machine screw. You could hold in place the wood vertical risers against the inwales with two or more screw fasteners.

Also, note in the drawing that the deck is reinforced with item "01", which is 9-inches wide. So the vertical riser board will be sitting on a reinforced section of the deck--and that is very good. Make the riser board 9-inches wide and you will be transferring the load onto the reinforced part of the deck.

I like your idea of using two narrower planks with a gap between them to allow better draining of water.