1995 Larson 174 SEI Complete Rebuild

[Woodonglass]

I'd put some fabric on too! CSM offer very little strength to the laminate.

 

[tpenfield]

Wow, you are setting a land speed record with this restoration. To add to WoG's comment, CSM is not very strong, whereas cloth will be much stronger. Also, keep in mind that if you do a lot of grinding, you will want to add back that material and cloth would be the way to go.

You could use resin/CSM on the transom between the fiberglass and the new wood core, as it will tend to take up any unevenness in the mating surfaces.

On tabbing the new structural members (stringers bulkheads, etc.) 1708 biaxial cloth is a good choice and the portion that mates to the hull will add back thickness that may have been depleted from grinding. You may want to add more thickness to the hull in other areas, depending on how much grinding you did.

Your experience in feeling how 'wobbly' the hull was once the structure was removed is very telling in that boat hulls are not very strong by the fiberglass alone. It is the structure that really makes it into something seaworthy.

 

[Mechanicalmike08]

Another good day of grinding, wish the wind was still here. My goggles really kept fogging up today, they were nice breaks but would have liked to keep on it more. I found the resin flat discs are best for knocking down the big stuff and edges and flap wheels work better for curved surface and smoothing things out.

Ill go with 1708 for the side walls after cleaning up the glue it's really thin.







2 questions
1. in the picture near the transom you can see the old tabbing, do you have to grind it all out even if it's in good shape and not delaminated?

2. The old transom angled down and had open space behind those angles, when I rebuild I will eliminate the angles and follow the flat section but put a nice radius at the corner. This way I can tab it all the way around. If I do it the way it was it will only be tabbed along the bottom and very top.anyone see an issue with this,my thought is it will be stronger this way

 

[Mechanicalmike08]

Wow, you are setting a land speed record with this restoration. To add to WoG's comment, CSM is not very strong, whereas cloth will be much stronger. Also, keep in mind that if you do a lot of grinding, you will want to add back that material and cloth would be the way to go.

You could use resin/CSM on the transom between the fiberglass and the new wood core, as it will tend to take up any unevenness in the mating surfaces.

On tabbing the new structural members (stringers bulkheads, etc.) 1708 biaxial cloth is a good choice and the portion that mates to the hull will add back thickness that may have been depleted from grinding. You may want to add more thickness to the hull in other areas, depending on how much grinding you did.

Your experience in feeling how 'wobbly' the hull was once the structure was removed is very telling in that boat hulls are not very strong by the fiberglass alone. It is the structure that really makes it into something seaworthy.

The wife and I have an understanding, I'm the kind of guy that when I have a project I eat breath and sleep it.

Ill be going with 1708 on the sides.

also found some wet and rotten heavy woven on the keel in the bilge area I will have to replace. It was only ran from the transom to the front motor mount. I will also be adding some woven in the hull where the rollers are to beef that up.

 

[Woodonglass]

If the glass is good and STUCK just scuff it a bit and clean well with acetone prior to laying down new glass. Use your own SPIT to coat the inside of your goggles lens. They Won't fog up if you do.

 

[Mechanicalmike08]

Not much new today, ground on the right hand side sidewall and cleaned the glue up. Ordered my glassing supplies this morning...ouch. tomorrow going to cut most of the deck lip out going to leave a small section near the rear to mark on the transom once it's in but then since it has to be up to the bottom of the bow I'm gona run a string line while making everything else.

 

[Mechanicalmike08]

Got some good work in tonight, got the deck lip cut out and ground except for a small piece to reference for running a string line. Finished most of the side wall glue removal. Another day maybe two and I can wash this thing out. You can see I marked where my rollers sit to reinforce those areas as well as a reference to see my bulkheads to knw if I got enough ground side to side for the tabbing to bite into.

Ill have to be careful cleaning it out because the foam is exposed in areas now.

 

[Mechanicalmike08]

I might have made a big no no… I realized today I didn't wrap the throttle or drive cable before starting grinding. Or the housing for the matter. Any idea for cleaning those up or did I just shorten the life of my cables?

 

[chevymaher]

Shop vac with a brush end. Then hit them with a air chuck and compressed air.

 

[Mechanicalmike08]

Shop vac with a brush end. Then hit them with a air chuck and compressed air.

I'll give that a shot tonight. Thanks

 

[Mechanicalmike08]

Well last night was the last grinding for a while. Touched up some spots and then gave her a good cleaning out. Blew it out with the leaf blower for a while and then finished by washing the hull out. Tried to stay away from the wall so the exposed foam didn't get wet. Just to be safe put some box fans in to dry her down over night. Its not completely over, once the stringers and bulkheads are in and i can find my new deck height there will be a little more clean up but shouldn't be to bad, the major grinding is over I hope.

Got my email last night as well, my US Composites shipment will be in Tuesday.

Going to make a template tonight for the transom and pick up some wood Friday. Hopefully I can have the transom and 2 bulk heads cut to shape before the glassing supplies show up.

 

[Bayou Dave]

Wow... you have done a lot of work in only a week! Looking good!

 

[Mechanicalmike08]

Wow... you have done a lot of work in only a week! Looking good!

Thanks, I have been busting butt. My first few posts were a little misleading though. Some of the work was done earlier this month. I think i started taking the interior out the first week of October, then it rained for 2 weeks and really started working when i took a half day from work i think the 12th. Will see if i can keep the pace, once winter hits my weekends will be taken up by winter hobbies. I really wanted the grinding to be done outside before I lost sunlight from daylight savings.

 

[Mechanicalmike08]

Not much progress the last 2 days, waiting on supplies. I need some comments. Made the template for the transom and am planning on this shape instead of the wings that floated I space like the old one. This way I can tab it all the way around. My only thought is the wings gave a little more torsional strength but im thinking I will gain that back by tabbing all the way around. Any comments?

 

[chevymaher]

It be fine that way. Alot of boats are made like that.

 

[Grub54891]

I did the same thing, only later I added in to fill the top open areas on each side with 1/2" ply and glasses over that. Figured it would get me a better place to attach wiring, ductwork, and things like that.

 

[AShipShow]

You'll be fine... if you wanted, you could fill those areas with urethane foam and make it flush so you can run one big piece of wood but that would probably lead to issues finding transom eyes long enough...

 

[Woodonglass]

Do you have Tow Eyes or access ladders needing mounted to the transom?

 

[harringtondav]

Not much progress the last 2 days, waiting on supplies. I need some comments. Made the template for the transom and am planning on this shape instead of the wings that floated I space like the old one. This way I can tab it all the way around. My only thought is the wings gave a little more torsional strength but im thinking I will gain that back by tabbing all the way around. Any comments?

My 174 SEI's first transom layer goes to completely down to the bottom of the transom/bilge, tabbed in completely with a hole drilled for the drain thru both layers. Like Frisco Boaters' "Big Mistake". The second, forward layer is set up, but I don't know why. See pic below.

I mention this because the stern drive applies It's pushing force thru the bottom of the gimbal plate. The out drive is a powerful torque arm, with huge forces (1000s of #s) trying to lift the bow from the transom. The trim rams deliver this force 1.5" below the gimbal plate lower pivot. So the forces are huge. The bottom of the gimbal plate is 3.5" above the keel.

So I'd recommend building the transom tabbed completely to the keel. This will give it maximum stiffness where it's most needed.

 

[Mechanicalmike08]

Do you have Tow Eyes or access ladders needing mounted to the transom?

The eyes come through the bigger square part and the ladder is off to the side in just the fibreglass but with a backer plate that I plan on updating as well.

Sounds like I'll stick with this concept. I will run it down more of the keel that cut was a little to big. I plan on doing it like Frisco and building up peanut butter down there instead of the wood for more protection but will glass over it