Bertram 20 Engine Bay

[Tundratom]

What’s the purpose of the added layer of laminate? Is the hull weak as it is?
Most Bertrams I’ve seen have robust hulls, and do not require additional layers of laminate. The original laminate encompasses the strakes. If additional strength is needed along the strakes, I’d consider adding mini stringers along their length rather than filling them in.
Large, flat areas of fiberglass are significantly weaker than same area with corrugations.

Re the stringers, they are intended to be continuous throughout the length.
Relocating them at a bulkhead will create a weak point along the bulkhead, however, adding engine room stringers close alongside them might allow them to be cut down somewhat in the engine area to improve access.
Another approach might be to allow generous longitudinal overlap, hopefully to the next bulkhead forward.

KapnD all good comments and I am not locked into any approach. I’ve observed a common practice of an additional layer on most Bertram 20 restorations I’ve seen over the past 3 years probably about 6 to 12 boats owners group on face book. Perhaps the age of a polyester hull, combined with removal and addition of material people are using an expoxied layer to tie everything together.


The mini stringers or beams make sense, but I was going to fill the strakes for easier laminating with less bending, so I thought there would be a place to add longitudenal reinforcement. If it’s just plane dumb, I can do mini stringers only. Comment?

I think I understand your comment about doubling up. Are you saying that cutting the stringers lower as they run close to the motor while running another set that are floor height (taller) close to them may be the answer? That they would not have to be sistered together? Lowering the height of the stringers along the engine would give me better access. I think your on to something!!

Could you give me a little more on the “generous overlap to” comment? You lost me on that.
Sincere thanks on this.

 

[kapnD]

KapnD all good comments and I am not locked into any approach. I’ve observed a common practice of an additional layer on most Bertram 20 restorations I’ve seen over the past 3 years probably about 6 to 12 boats owners group on face book. Perhaps the age of a polyester hull, combined with removal and addition of material people are using an expoxied layer to tie everything together.


The mini stringers or beams make sense, but I was going to fill the strakes for easier laminating with less bending, so I thought there would be a place to add longitudenal reinforcement. If it’s just plane dumb, I can do mini stringers only. Comment?

—Again, do you really need reinforcement? The stringers alone should be enough reinforcement to keep the hull from flexing. Filling the strakes and glassing the entire bottom does very little towards strengthening the hull, only adds weight and lots of unnecessary labor.


I think I understand your comment about doubling up. Are you saying that cutting the stringers lower as they run close to the motor while running another set that are floor height (taller) close to them may be the answer? That they would not have to be sistered together? Lowering the height of the stringers along the engine would give me better access. I think your on to something!!

—Yes, lower the stringers through the engine compartment, but cut them down diagonally to create “knees”.
It may be possible to compensate for lost height by making them stronger by wider, or heavier layup, dimensions and calcs necessary.

Could you give me a little more on the “generous overlap to” comment? You lost me on that.
Sincere thanks on this.

Im saying that if you expect the new, wider spaced stringers to act as more than deck supports, they must be somehow structurally tied to the exist. Offsetting stringers at the bulkhead destroys their continuity.

 

[fallguy]

What parts of the engine are below the stringers?

If you are talking about oil changing; guys have modified that by piping a drain line.

The plugs and cap and all that are up high, so I still don't understand how changing stringers helps with engine access.

Modifying the boat for oil changes is not done.

 

[kapnD]

What parts of the engine are below the stringers?

If you are talking about oil changing; guys have modified that by piping a drain line.

The plugs and cap and all that are up high, so I still don't understand how changing stringers helps with engine access.

Modifying the boat for oil changes is not done.

.

Good access is key to good maintenance!
Did you see the pics of the old motor?
The OP is redesigning to eliminate foolish features that the industry regularly forces on buyers.
There’s always room for improvement, I don’t think I’ve ever had a boat that I didn’t modify,

 

[fallguy]

.

Good access is key to good maintenance!
Did you see the pics of the old motor?
The OP is redesigning to eliminate foolish features that the industry regularly forces on buyers.
There’s always room for improvement, I don’t think I’ve ever had a boat that I didn’t modify,

Modifying stringer locations to change oil? Come on. You even said he needs continuity.

I asked a simple question. What part of the engine access is below the stringers?

 

[mudsailor]

What height is the floor above the keel line? what distance off centerline are the stingers?

typically on a 20ft boat floor height would be 14” to 15”, (350 to 380 mm ) which can make it hard to access under the engine from the sides (and the exhaust can get very close to the structure as well) What I would do is just lower the stringers as they go aft and if you need floor support then add a removable support (nothing fancy, a board with a couple of boats would work)

 

[Tundratom]

Hey Guys, the focus on oil changes is a bit mis-placed. If that was my primary concern I’d bring it to a service tech. I will be doing all work going forward and have two bad shoulders, rotator cuffs. Extra space in the motorwell is not a luxury. I’ve gone back and forth on IO vs OB, and I think the expense and mods of switching to an OB is not in the cards. Thanks

 

[Tundratom]

Hey Everyone,
Thanks for thoughtful discussion on the engine bay. I want to start a discussion on fuel tanks, daisy chaining two tanks. Should I start a new thread under another forum or should I continue here? Any suggestions would be very helpful. Thanks Tundratom

 

[bajansailor]

Please do carry on here with your questions re the fuel tanks - I think it would be easier to keep it all in one thread rather than starting a new thread every time.

 

[Tundratom]

Broke wrist Tuesday night. Things will be delayed. Thanks everyone. Will try and post fuel tank issue soon.

 

[bajansailor]

Oh dear, that looks like a nasty break - but some impressive engineering has gone into fixing it.
I hope that it all heals well now, and that you are not out of action on the boat building front for too long.